A tour of our air-to-air heat pump system - heating AND cooling

We had our air-to-air heat pump system installed a month or so ago (AC units in other words) and in this video I'll take you on a tour of our house to show you what we got and where it's all installed. I'll also tell you the full cost and show how loud the indoor and outdoor units are.
00:00 Introduction
01:44 House floor plan
05:48 System hardware specs
09:44 Cost
12:08 Hall
12:48 Lounge
13:25 Hall indoor ducting
13:55 Wall core samples
14:17 Hall outdoor ducting
14:34 Hub area
15:44 They're like a fridge
16:33 Bedroom
17:59 Office
18:25 How loud are the indoor units?
19:24 Outdoor units
21:18 How loud are the outdoor units?
22:10 Closing thoughts
23:05 Bonus defrost cycle
Please note that Tim is not a professional consultant, just an enthusiastic amateur, so cannot reply to requests for advice or opinions on specific systems or green investment opportunities. Thank you for your understanding.
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[@craigsanderson2858]

Many thanks Tim for the super videos on this topic. I lived overseas for 30 years (mostly in Hong Kong) and I recall our living room split AC and heating system breaking and needing replacing. The cost of the outdoor and one indoor unit for both heating and cooling was around GBP1,000 including installation (28 floors up - so the installers had to work at considerable height). Therefore, I'm concluding that while these UK Air2Air systems are superb, we are being taken for a ride financially and that in reality given these are not new tech and been around for ages should be at least half the cost they are in the UK. Again, thanks for the video and I personally appreciate the time taken and quality production.

[@TimAndKatsGreenWalk]

I believe the reliability is improving all the time so hopefully they're better nowadays, but time will tell! And hopefully the prices will start coming down too as more people get them installed. Prices for a lot of equipment have been unusually high recently too.

[@ched999uk]

Very useful especially the layout and pipe runs, gives us some new ideas. Thanks.

[@MisterTea74]

Thank you, I’ve found your videos very helpful. I have solar panels, a zappi and an eddi and have recently been thinking about a battery (libbi) your clear information has been really useful in heloing me to understand the pro’s and con’s of doing this. I’ve looked at numerous sources but yours are the clearest and easiest to understand.

[@TimAndKatsGreenWalk]

Thank you, that's kind of you to say. I'll hopefully have plenty more videos to come on all sorts of subjects as we get further along our journey so I'll try to make sure they're just as helpful.

[@soundslight7754]

Very grateful for this open and honest video presentation. Really useful information

[@rashpalsidhu]

You're doing fantastic work and really help me and many others understand transitioning to green energy.

[@TimAndKatsGreenWalk]

Thank you very much, I appreciate that.

[@daveg56]

Thanks Tim, that's so helpful to understand what heat pumps are all about from a practical point of view. I really appreciate all the effort you and Kat put into the videos, we're about to embark on our own journey which was kicked off when getting an EV 3 years ago. Next stop, solar and battery!

[@TimAndKatsGreenWalk]

Nice!

[@jeanh9641]

Thanks, Tim. This video was so informative. It certainly is something I shall look at when the time comes for me to give up gas. I am at the beginning of my green journey.

[@TimAndKatsGreenWalk]

No problem, I'm glad you found it useful.

[@lyracian]

Great video and wonderful system. Very helpful for me to plan out my installation for next year.

[@TimAndKatsGreenWalk]

Glad I could help.

[@Japnut]

Glad I discovered your channel today. We have been on our green journey for a while from shampoo bars and milk bottles to 2 evs and solar battery install. Looking to develop more. Biggest saving for us has been the evs. We run 2 older evs (2016 ioniq 28kwh and a 2015 leaf) they are brilliant! Air source heating is next on the list as we want to stop with gas dependancy.

[@TimAndKatsGreenWalk]

Great stuff. Our EV is now due in Jan so looking forward to that.

[@SuperDiagnostic]

Well timed Tim.. Am just in the process of getting a ASHP A2W fitted and on researching have seen lots of comments regarding A2A. ThnX

[@TimAndKatsGreenWalk]

I'm glad to hear it. I'm hoping this series will help some folks who are currently undecided.

[@michaelridley2864]

Thank you - really interesting and clearly explained. Looking forward to the next two videos.

[@TimAndKatsGreenWalk]

You're welcome. I'll try to get the next video out in short order.

[@petanders1968]

Tim Nice video on your system. We had 3 Air 2 air Daikin units installed in Aug 2021 in our bungalow and have not used our boiler since mainly because it failed and we decided on an alternative heating/cooling arrangement. We have a 2.5 kw unit in bedroom 1, and 3.5 kw units in bedroom 2 and lounge and so far the temperatures have been very comfortable in both hot and cold conditions. We are gradually removing our ch radiators as the boiler is no longer used and still have the electric hot water immersion tank for heating the shower and sink unit. Your Toshiba units are very nice and we like the alternative covers ,ours are white but all our rooms are white too so this is ok for us. Our units are fitted onto the building external brickwork at the gutter level so as to maintain adequate space around the buildings ground level for parking and access. We opted for vandal proof grills on each unit just to be on the safe side and they also stop pests like birds, cats etc. Your installers made a good tidy job of hiding your pipework inside and out, our pipework is a bit naked so we may get them to fit some ducting tunnelling for cosmetic purposes the next time they do a service call to the refrigerant. Each unit has a remote and like yours can be connected to wifi which we may do sometime. We've been through 2 summers now and enjoy the AC mode when its a humid muggy day/evening. Like you we are replacing our old lighting for led light fittings in each room and may go the solar roof in the coming years. Enjoy your setup , all the best Peter

[@TimAndKatsGreenWalk]

That's great to hear. I'm certainly looking forward to next summer when I can make use of the cooling mode, especially because I'll be able to run it for free with the solar panels (assuming they've been installed by then!). We're also planning on getting rid of our radiators once we're happy that the AC units provide adequate heating over the rest of the winter. So far it's looking very promising, and it was totally up to the job even when it dropped to 0 deg C a couple of days ago.

[@kevinceney]

Thanks, Tim, for your videos. I'm looking into buying a similar system so this is amazingly useful.

[@TimAndKatsGreenWalk]

You're welcome. Good luck with the install!

[@nicdensley4104]

Very useful for me, thank you, I'm looking at a similar set up for my house so was good to see around it.

[@TimAndKatsGreenWalk]

No problem, glad it was helpful.

[@peterbunker7165]

Jolly interesting, thank you.

[@ashtonwoodturnings225]

Very interesting for cooling in summertime and will revisit, if and when you show cooling, But thank you for the video

[@JJ-zg1hh]

Great video - I've subscribed! The main discussion in the UK seems to revolve around air to water heat pump systems. Personally I prefer this air to air set up with an unvented electric hot water cylinder for DHW. Freeing up radiator space is so useful, plus these systems cool your house during hot summers which is fantastic.

[@TimAndKatsGreenWalk]

Yup, looking forward to trying these out during the next heat wave!

[@BarryHaegerSalesCoach]

From the decisions I've had I've been told that the object of the government initiative know as the Boiler Upgrade Scheme or BUS, is to reduce the UK energy requirements and while both air to air and air to Water ASHP will displace Gas for heating, because Air to Air will also be used as AC in summer months it increases electricity demand in summer which is already a problem particularly in cities.

[@roncritchlow6793]

Thanks Tim, great resource 👌🏾

[@andrewdeacon4384]

Very interesting Tim. Thanks for uploading.

[@TimAndKatsGreenWalk]

No problem.

[@lekago]

That actually was very useful indeed, thanks a lot!

[@TimAndKatsGreenWalk]

You're welcome

[@dontuno]

Many thanks for the video and details of your installation. We have a mini split system specifically for our bedroom. I've noticed as a heat pump it is actually very economic and throws out a very pleasant heat. I'm now seriously looking to install another system to cool/heat another bedroom and our dining room whilst leaving our conventional system in situ. I'm sure I and many others would be interested to see your cost comparison with your previous heating method.

[@TimAndKatsGreenWalk]

I've mentioned this in a few of my other videos (I do a monthly stats video covering solar generation and other stuff) but generally it would be similar to running a gas boiler if we didn't have the solar and battery system too, but with those other things it becomes considerably cheaper to run than gas because I can charge up our batteries overnight at cheap rate to help support the heating during the day.

[@Danothebaldyheid]

Thanks - very helpful and informative..

[@grahamlochrie9918]

Thanks for the video for the air 2 air system we are also considering installing it in our property waiting for more information on the running costs. For the last year we have got rid of gas hob gas fires installed a mixergy hot water tank and solar and givenergy system which is working amazingly well looking forward to your next video

[@TimAndKatsGreenWalk]

Glad to hear it. I'll be showing more data on the running costs in this series so hopefully that'll be useful to you. A quick spoiler though: so far the cost has been pretty similar to running the gas boiler. But I'll go into more details in due course.

[@grahamlochrie9918]

Thanks for the reply looking forward to the next video are u explaining the amount of load each unit is using also how temperature outside affects the efficiency

[@TimAndKatsGreenWalk]

@@grahamlochrie9918 It's not possible to measure the actual efficiency with respect to temperature, but I can show the daily energy use for different outside temperatures. I've been recording that data and intend to show it all in exhaustive detail!

[@humphreybradley3060]

Excellent video Tim. We moved into a new build in 2020 (we didn’t build it), which already had a Vaillant 15kW ASHP. We added 6kWp of solar & a Powerwall. What we did notice is that, particularly in summer the house became very stuffy; leaving windows open isn’t an option, so we’ve installed an MVHR system to the top floor to improve air circulation, cooling & to help the heating system during the winter. I guess this is where A2A has an another advantage in that the air is recirculated etc constantly?

[@TimAndKatsGreenWalk]

Yes, these units just recirculate the air, there's no ventilation. Does your MVHR have the option for recirculation, out of interest?

[@wajopek2679]

All things considered, a very nice installation covering 2/3 of the property. I guess it will cool in summer too. Now need solar panels to power those kW's.

[@TimAndKatsGreenWalk]

Yup, we've been waiting for the PV installation for quite some time. Soon, hopefully.

[@nickieredshaw7835]

Thanks a lot for a great video lots of great info

[@TimAndKatsGreenWalk]

No problem, I'm glad you liked it.

[@Extragonk]

Super interesting stuff, thanks! Looking forward the next ones too, it'd be interesting go deeper in the software side too.

[@TimAndKatsGreenWalk]

Sure thing. Do you mean the app? I'll make sure we cover that.

[@Extragonk]

@@TimAndKatsGreenWalk yep, as ive seen in other systems, the software can make or break the hardware if it's done badly

[@Daniel-gl3si]

Very interesting Thank you

[@TimAndKatsGreenWalk]

No problem. Thank you very much for the super thanks, that's very kind of you.

[@denniscarvell1828]

Hi Installed split air con four years ago, Found the installation reasoning in most respects unusual.

[@TimAndKatsGreenWalk]

Not sure what you're saying here.

[@r3dsouza]

Thanks Tim, for a very comprehensive video. I'm looking forward to your next couple of videos. Please could you include what is the peak power usage when keeping all the units running.

[@TimAndKatsGreenWalk]

Yup, absolutely, we'll cover everything in exhaustive detail! So far though they tend to tick over at about 1-1.5 kW to keep the house stable when it's about 5 deg outside, but sometimes as low as 0.5 kW if it's closer to 10 deg outside.

[@r3dsouza]

@@TimAndKatsGreenWalk Thanks Tim. The reason I'd like to know is to be able to size the battery storage capacity and the inverter peak output. Looking forward to your next videos!

[@TimAndKatsGreenWalk]

@@r3dsouza good stuff. Yeah, I'm looking forward to getting our PV and battery system soon, hopefully. It won't totally cover the heating but should give us at least some using stored cheap night rate energy (unless Kat let's me get more battery capacity!)

[@michaelrussell8921]

Bit of charing on the indoor dining room unit coil. Hope that's normal? Was suprised to see extension leads in use, thought the units would need 6m2 cable to operate. Great video. Thank you!

[@TimAndKatsGreenWalk]

Each unit is 10A max, no problems running off standard 13A extension cables (one each, obvs).

[@mirko2378]

Veramente elegante pulito silenzioso grazie mille video ho già ordinate 😁

[@TimAndKatsGreenWalk]

Glad I could help.

[@RobFisherUK]

I have a similar system. Two outdoor units and 5 indoor. Mitsubishi Electric fwiw. I kept the gas central heating so I can directly compare costs. What I've ended up doing is running the gas heating for a couple of hours in the morning because that warms places the AC does not reach, like the bathroom. But after that, when working from home it's much more efficient to heat just the one room with the AC than to run the gas heating, even with TRVs turning off most of the other radiators. I use Home Assistant to monitor power usage in various places. One experiment I ran on two consecutive cold days in December (about 0C outside) I heated the kitchen diner where I worked for 9 hours. With gas it cost £2.36 for 23kWh and with the AC it cost £1.62 for 4.6kWh of electricity. Another time in the warmer part of December I used gas as needed all day for 5.76 and then AC all day for 2.86 (either with TRVs on a schedule or the AC heating whatever rooms were in use). It's also much quicker to heat a room than the gas, so when people go to bed I can heat the respective bedrooms for just 30m or an hour to take the chill off, whereas I would have had to run the gas heating for much longer to get the same effect. One thing you did not mention in the video is the defrost cycles: indoor units make a noise a bit like a boiling kettle when this happens. No big deal in the day. The other day it was extra cold out and this was happening quite often (about every 30 minutes). I got annoyed mainly because the unit blew room temperature air around making a draft for a minute or so each time. But other than that I have no complaints, and normally this only happens on days below 3C every few hours. Another thing to consider is the standby power usage of the system. My system uses about 30W just doing nothing. 0.8kWh per day. You can't turn it off because of the refrigerant leak detection. It's great being able to just turn it on when I feel a bit chilly without using tons of energy. And the rate it uses energy is pretty low. The whole system running full tilt (which never really happens because we don't use all 5 rooms at once and it's rarely cold enough to make it work at max power) maxes out at about 2.5kW. If you have solar you can probably run it for free for much of the day even in winter. And the reason I got it in the first place: it will be very handy for the next heat wave!

[@TimAndKatsGreenWalk]

I did mention the defrost cycle, right at the end of the video. Even showed a little clip of it happening! Although admittedly I didn't go into many details. Also, there are a few other videos on the channel now going into more details about how Kat and I have found living with it. So far it's been pretty great so also no complaints from us and we're glad we did it. Your comparisons against gas are really interesting. I've not done as many experiments as you just yet but I reckon it's working out about the same in terms of running costs but it's pretty hard to do accurately. In any case we've found it more comfortable overall so are very happy with how it's working.

[@RobFisherUK]

@@TimAndKatsGreenWalk this is why I shouldn't start typing the comment before I finish watching the video! The experiments are mostly just reassuring me I can use it how I want without incurring silly costs. I doubt it will ever recover its cost unless I get solar as well. Glad it's working well for you, anyway!

[@David-bl1bt]

An interesting and informative video, thanks for taking time-out to share your experience. In the section of the vid showing the outdoor units I noticed the green colour brackets, I'm wondering if you are planning installing some sort of canopy over that path? I'd so, will boxing the units in by putting a roof affect their performance? The defrost cycle is interesting. How long does it take? as there is no heat provided into your home during this cycle, how much does this impact the comfort level in your home? I'm looking forward to further videos on this topic.

[@TimAndKatsGreenWalk]

The canopy doesn't extend as far as the outdoor units, it only covers half that side of the house, so doesn't box them in and the end of the passage is still open too so plenty of ventilation even with the roof over that part of it. The defrost cycle took less than 10 mins, probably closer to 5. So it was just a brief pause before it started heating the house again.

[@MCSMIK]

Very very useful and interesting video Tim. I am planning to install air to air in our house, which funnily enough is extremely similar new build to yours, albeit I think your house is a bit larger. I have a 12kWh battery at home, with easy expansion capability. I'd love a video on the consumption figures of this, and particularly the power drawn on average. As whilst those units are rated high in capacity I'd expect them to be drawing much less power especially at the minimal fan speeds. We can make it through the day with just the house use from our 12kWh battery, having charged it up from Octopus Intelligent hours (only really need 2 hours to fully charge as I've got dual inverters). Over 95% of electricity we use currently is off peak, whilst solar is non existent in december. So it begs the question how massive my battery needs to get to support a heat pump purely from off peak rates :D 48kWh minimum I'd guess

[@TimAndKatsGreenWalk]

Yup, I'm still gathering data but will be doing a full report on the energy usage in due course. As it happens I did another video a couple of months ago about whether or not it would be worth getting a second battery to help cover the heating costs (using simulations) and although I'll be revising that with some real data the conclusion will be much the same: you would indeed need a rather large battery to cover it all! A quick spoiler though, when the outside temperature was well below 0 a couple of weeks ago we used 34 kWh per day, but at the moment with it 5-10 deg outside we're using closer to 15 kWh per day. And yes, they don't usually get anywhere near their full power draw, we typically see them max out at 1 kW each, but at the moment it's less than 1 kW between the them.

[@technretro7115]

Interesting video, very informative. It would be interesting if you have pictures of the pipes inside the ducting as they are quite long runs on the outside of the property.

[@TimAndKatsGreenWalk]

You'll see some clips of the pipes in the video I'll be publishing later today.

[@ianstubbs8567]

Thanks for sharing info & very interesting to see as I see more the cooling usage as we have shorter springs & longer summers with higher temperatures to work with or avoid, I have 4.65Kw of solar & 9.5Kw battery so I would see that cooling will be primary usage & as longer term ... if ever happens when electrical usage prices drop to somewhere more real at 4 or 5p per kWh considering all the wind farms & solar etc. of course we have heard the story many times that electrical power will be more or less free as in the 60's due to nuclear power. Sorry I am that old to remember the 3 day week & power cuts. So to balance change from gas central heating to electrical heating I think this is the perfect step as you achieve the best of all worlds cooling & heating. The transition from gas to anything will be long & in most cases painful as current boiler technology has no 100% hydrogen & at best we go back to when we had town gas which was 20% hydrogen from coal fired power stations mixed with 80% natural gas .... as they say history often repeats itself.

[@rcosnett]

Very interesting, the ducting would be a problem, the running cost will be very interesting.. Bob

[@TimAndKatsGreenWalk]

If the indoor units can be put on external walls there is no ducting inside. There will always be some external ducting though.

[@petervince4710]

Tim & Kat, thank you for taking the time to produce the video. I am looking at A2A for our property. Due to the 2 up stair bedrooms being in the roof space, the ceiling is at a 45 degree angle, coming down to a 1 metre high wall. This means, that we will have to install an A2A unit at this lower level, which looks like a storage heater. Does anyone know if these lower units are not as good as the units that are placed higher up? Just thinking about the air flow being better higher up. Also if we have installed units in rooms that we don't use very often will these still consume electricity, albeit on a number of watts. I am not sure if these units can be turned off individually. Of course it all adds up. Thanks for any reply.

[@TimAndKatsGreenWalk]

The individual units can be turned off, they are all independently controllable. As for floor units, those can work very well for heating since the heat will start low down and rise up naturally, like with a standard radiator. They won't be quite as good for cooling, but will still work.

[@richardc1983]

The floor units are brilliant at heating, when I had wall-mounted high-up units (like Tim;s in the Video) I also had a floor-mounted unit like you are thinking of. These warm better as they blow warm air out at feet level across the floor and warm air rises so it warms the room more evenly. In cooling, they blow air up towards the ceiling and work really well just as well as other units. No issues at all. Cracking units...

[@EddieGittins]

consider the Sensibo Controller and App. it’s pretty good

[@TimAndKatsGreenWalk]

Ooh, I'll look into that, thanks!

[@johntisbury]

Thanks for this information, tour and details. Very useful. Do you have a soak away for the outside units?

[@TimAndKatsGreenWalk]

Yeah, there's a strip of gravel either side of the path where the outdoor units are sat and that seems to be sufficient so far. There was a bit of ice buildup on the path in the sub zero temperatures the other week but that all melted away after with no problems when it warmed up a bit.

[@keypoint1293]

I lived with split AC for years in hot climates no problem with noise. It certainly seems much simpler and better solution air to water heat pumps.

[@TimAndKatsGreenWalk]

It's been working well for us.

[@solexxx8588]

While air to water is more thermally efficient, it's important to match the unit to your climate and building. If you already had hydronic in-floor heating, air to water is easy and super comfortable. Radiant heat feels warmer for any given setpoint and heats big wet things (like us) directly with infrared electromagnetic radiation.

[@TimAndKatsGreenWalk]

Oh, if I had already got an underfloor system I would totally have gone for A2W.

[@jamesw7786]

This video was brilliant! Thank you for uploading, it answers so many of the questions I was wondering, for example what the internal and external ducting would look like. I was concerned about having to have isolation switches all over the place too, but electrically all of this can simply be plugged into an outdoor double socket? Does that have to be on the ring main, or can it be a spur, or does it have to be a dedicated run from the consumer unit? How did you go about finding your installer? The ducting looks so neatly done! Thanks

[@TimAndKatsGreenWalk]

Thanks, I'm glad you found it helpful. The ideal solution is wiring the units into a separate block on the consumer unit but if you have a beefy enough ground floor circuit it's possible to add a spur (our ground circuit is 32A so has plenty of capacity, since the kitchen is on a separate circuit too). I found the installer by searching for local air conditioning installers, simple as that.

[@jamesw7786]

@@TimAndKatsGreenWalk great thank you for the info. I’m hoping the electrician can wire it in such a way that it could be powered both by the house, or by V2L from the EV

[@uknick]

Hi Tim another very clear and interesting video. I have both air2air (AC) and air2water (ASHP) heat pumps the latter was installed in early 2021 through Green Homes Grant the AC a couple of years earlier. I have a 4 way multi split Mitsubishi AC unit that feeds the upstairs bedrooms and my sitting room. So basically I can compare the effectiveness and the running costs of both systems. I find the ASHP cheaper and more effective and so rarely use the AC for heating - it’s primarily for cooling in summer. I would be interested to see your data for electricity usage/cost especially for these colder days. As a data point yesterday I used a total of 32kWh and I ran the ASHP all day with indoor temps of 20 first thing 18 during the day and 20 in evening outside temp day was a chilly 4 degrees. The previous day I used AC tactically to keep house warm ding the day and used an additional 10kWh at a cost of34p/kWh that’s an additional £3.40 I think that using AC units is really good for rooms or smaller spaces, but I’m not so sure it works so well for a whole house. Anyway good video and fairly unique in terms of exploring the use or Air2Air heat pumps for heating in UK 👍

[@TimAndKatsGreenWalk]

That's an interesting comparison. I'll be showing some more data about the energy consumption under different outside temperature in the following videos, so hopefully that'll be illuminating. But as a quick preview when the temperature hit 0 deg C last week we used 20 kWh for a day's heating but that was to keep the smaller rooms at 18-20 deg and the open areas (hall and hub) at 16 deg (since we tend to pass through those rather than spend a lot of time loitering there!). If we'd used another 5 kWh I reckon the whole house could have been kept at 18. When it's about 5 deg outside we're typically using about 15 kWh per day. I think if you have enough indoor units you can easily heat a whole house with A2A, but it needs to be managed in a slightly different way to A2W, I suspect. We're still trying to find the best way to manage it and I'm sure we'll get into a good rhythm over the course of the winter.

[@KevinArmstrongUK]

The newer units with R32 refrigerant have a much better efficiency over units with R410A. Just something to consider when comparing new A2W vs older A2A

[@uknick]

@@KevinArmstrongUK mine are R32 also and have a COP of over 4

[@uknick]

@@TimAndKatsGreenWalk is that 15kWh for everything or just the heating. Another interesting observation is that those of us converting to heat pumps and electric heating are more likely to turn down the temperature to c16-18 degrees whereas when we are heating with gas we would probably just have set the thermostat to 20 and accepted that it wasn’t necessarily optimal. That was because until recently gas was artificially cheap compared with electric c2.5p vs c15p for electric now with gas at 10p with efficiency of 80% electricity and a heat pump at 2-300% efficiency even at 35p /kWh. Interesting behaviour changes!!

[@TimAndKatsGreenWalk]

@@uknick that's just the heating.

[@brackcycle9056]

For readers Reference an A2W seems to be costing £7K-12K+ including hot water tank after BUS grant, ( replacing micro bore or UFH extra) Octopus are much cheaper but only do easy homes. With A2W the house heats slowly because you only get one HP sized as small as possible for max efficency & it likes being left on at 15c when you are on holiday. Annual service for A2W seems V expensive at the minute £200-£300 gets quoted.

[@TimAndKatsGreenWalk]

That's handy information, thanks for sharing it.

[@edwardpickering9006]

Interesting to see you have tiny radiators in your new build house - just like mine! Are you planning to remove them or just leave them in place? Also consider putting electric immersion heaters into your existing bathroom towel rails, saves having to swap them.

[@TimAndKatsGreenWalk]

Yup, we'll probably get rid of the radiators in the Spring. We considered getting immersions for the towel rails but we don't like the actual rails themselves so this is a good opportunity to change them!

[@edwardpickering9006]

@@TimAndKatsGreenWalk New Build Problems!!! ;-)

[@TimAndKatsGreenWalk]

@@edwardpickering9006 yes indeed.

[@brackcycle9056]

Very encouraging . Neat simple & straight forward. Do you need planning permission / DNO approval/ or pass the same " noise a neighbours window" calculation as Air 2 Water heat pump ? I see there is no roof on your alley where they live , thats good . . It would be interesting to measure the outdoor unit intake air temperature , compared to the rest of the garden , to check the slatted fence is not causing a cold canyon. Do let us know the servicing charges.

[@TimAndKatsGreenWalk]

Planning permission is usually not required if the outside units are small enough (

[@KevinArmstrongUK]

Love this Tim. Could you do a vid on running cost.

[@TimAndKatsGreenWalk]

Yup, that'll be part of video 3, or maybe a bonus fourth video if we can't make it fit.

[@KevinArmstrongUK]

You got me thinking on our hall. I decided that i wouldn’t heat it as seemed daft to heat a room we only use to move through. But the heat would rise and heat the landing too, so now I’m second guessing myself.

[@TimAndKatsGreenWalk]

@@KevinArmstrongUK yeah, we tend to set that hall unit at a lower temperature than the rooms (16 or 17 deg) since we don't spend much time there, but it's nice to keep the core of the house heated a little bit.

[@connorjohnston3022]

I’ve installed a number of Toshibas, they’re a pleasure to install and work on and are great units overall but that infrared remote is a pain in the butt to switch modes and louver direction on

[@TimAndKatsGreenWalk]

Yeah, I never use the remote, I always just use the app. The app isn't great either, but it works well enough.

[@ungrim97]

Having just decided to get a Toshiba Haori installed along with a Ducted unit in the loft. Thanks for the info, was super helpful in the decision making process. OOI did you consider a ducted solution for upstairs at all?

[@TimAndKatsGreenWalk]

Well, sort of, I only really considered it after we'd got the system installed! I learnt about it slightly too late, but it's definitely something I would have investigated further had I known more at the time. I believe it would have been more expensive to install, however, so it may not have changed what we did in the end. Although having lived with the system for a while now I think a ducted system upstairs would have been the right choice, even if it cost a bit more.

[@richardc1983]

Absolutely brilliant video and a lovely home too, go ery light and airy. Great detail. I think I'd be tempted to put a 3rd unit on the unit that does your master bedroom and kitchen diner and out a ducted unit in your loft to supply the other bedrooms. Great looking unit so too. You tend to mount them so the units blow down the longest part of the room to discourage short cycling of air. The unit in your kitchen will heat really well, I like the fabric finish of it. How are you finding the temperature control do you leave on 24/7 but at a lower setpoint when you are out or in bed? My multi split system (ducted in every room) we leave at 18c when out or in bed so the house doesn't drop too much as if we use the on off method. Them all starting up at the same time means the unit is working very hard to heat the house up, whilst there is plenty of capacity there this results in more frequent defrosts of the outdoor coil. What is your comfort setpoint you find? A little tip, when running them in cooling make sure you have plenty of fresh air diluting the recirculating air otherwise the odours in the air and breathing out etc will collect on the coil resulting in smelly coil (a bit like sweaty socks or cat pee). Worth installing something that will bring fresh air in or make sure a window ajar.

[@TimAndKatsGreenWalk]

Thank you, I'm glad you liked the video. The outside unit with the spare output is already near maximum capacity, unfortunately, as it's supporting the more powerful hub unit, as well as the bedroom, so adding another unit to it would reduce the output of those other two. And since we don't use those other bedrooms that much it's cheaper and simpler to just add electric radiators and use those for the few days a year we'd need those rooms heated (we actually leave the doors open and let the hall unit do some mild heating in those rooms in any case, they'd just need a boost if we had guests staying). We're still experimenting with the controls. We started with ad hoc heating as required but as it's gotten colder we're tending to leave them on most of the day and just vary the set point temperature if we're in or out of any given room (19 while in a room, 17 when not). The latest experiment (starting today) is to leave them all on at a reasonable set point (18 or 19 depending on the room) and have them set on timers so they come on a little before we get up and then turn off just before bedtime. We're also having them come on for the four hours of cheap overnight rate since that costs us very little. So in total they'll be running for about 18 hrs per day. Hopefully that'll result in less micromanaging and a more comfortable level temperature, at the cost of slightly higher energy usage (although this experiment is to find out how much more compared to what we were doing last week). Great tip for the summer, we'll make sure to remember that.

[@richardc1983]

@@TimAndKatsGreenWalk Great stuff, it's all about tinkering and finding out what works for you. They do generally work best if they are set so that the building fabric doesn't drop too low. If we turn ours off completely then it can struggle to get the house back up before we are comfortable. As there is no radiant heat which with rads you would feel warmer at a cooler flow temp as the radiant is what warms you first. Also run everything in low fan speed so that the heating on cycle (where indoor unit has demand for heating) runs for longer. This ensures maximum efficiency you want to keep that outdoor unit running for as long as possible just ticking over.

[@TimAndKatsGreenWalk]

@@richardc1983 yeah, we generally run the units at their lowest fan setting. It's going to be interesting to see how having them on for longer works out over this coming week. We might well end up leaving them on overnight too and just setting the temperature a bit lower, as you suggested. Experimenting is all part of the fun! And we'll be reporting the results of all of this in the third video in this series when Kat and I sit down and chat about our experiences so far. That'll be in two or three weeks' time, I expect.

[@richardc1983]

@@TimAndKatsGreenWalk The biggest thing we missed is radiant heat... we now have a wood burner to give us that and also an Warrmlite WL42013 1kw carbon heater from Amazon. (argos used to sell but couldn't keep up with demand) cheap to run at only 500w on low and 1kw on high (never need it higher than low though as it's like being on fire) these are not to be confused with those god awful halogen floodlight type heaters that blind you with bright light!

[@TimAndKatsGreenWalk]

@@richardc1983 so far we've not missed the radiant heat but we'll see how we feel over the rest of the winter.

[@stewreviews9345]

Thank you. Interesting stuff and great to see in real world use. What about monthly running cost compared to gas? Do you have data for comparison (I could see your old radiators still in situ)? Also, could the exterior units have been raised?

[@TimAndKatsGreenWalk]

I'll be covering the running costs in the follow-up videos but so far it's been comparable to using gas. The radiators will be removed in the spring, probably, once we're happy that the system can cope all through the winter. I'm pretty confident we won't need the gas heating on at any point though as it got down to 0 deg C last week and the new system coped just fine. The exterior units could be mounted on the wall but it makes installation and maintenance much harder. Definitely an option though, if required.

[@1943L]

Excellent video and facts. Was there a grant for this?

[@TimAndKatsGreenWalk]

No, unfortunately A2A doesn't qualify for the boiler upgrade scheme, unlike A2W. Bit of a shame but usually it costs less to install in the first place.

[@ianwilliams5915]

Those indoor units look fine, better than I thought they would. The indoor trunking also not too bad. Routing through the loft space would of been neater but you explained the drain downwards reason. You have the outdoor units shielded by the dance which makes your installation fine. Many people however do not have this and they remain unsightly to many. The manufacturers need to consider the looks of the units imho. The units are to many noisy though and if you latch onto the noise then it stays with you.

[@TimAndKatsGreenWalk]

I showed how quiet the units are, they really are very unobtrusive, both inside and out. They're much quieter than they were a few years ago and are getting quieter all the time.

[@ianwilliams5915]

I hear what you said in your video and the reply to my comment. I agree that the noise produced by the external fans mixes with the ambient background noise to some extent. My neighbour has recently has installed a setup similar to yours and whilst the fan noise is generally low I can still hear it from 20 meters away. Indoors without the outside ambient noise it’s a low frequency hum which is as you can imagine is not good. Whilst for some and you this may not be an issue, all I was trying to say in my reply that it does & will for some. A point about your installation, the outdoor units need to be at least one meter away from your boundary. This is required by law - your installer should of known this.

[@TimAndKatsGreenWalk]

@@ianwilliams5915 It's not a requirement by law for the outside units to be more than 1m away from a boundary, you just need planning permission.

[@ianwilliams5915]

So since you have more than one pump and position so close to your boundary then I take it you have planning permission. Just because you’ve done this it doesn’t make it right.

[@colingoode3702]

Hi Tim. Those Toshiba units look good. I believe the 0% VAT on heat pump ruling came in April 2022. Previously it had been 5% VAT for heat pumps installed in domestic premises. Just to clarify that should be 0% VAT on the equipment & all "associated" installation materials & labour which I believe is the same for Solar PV systems as well. Interestingly, the EU Supreme Court had previously deemed the UK to be in breach of EU law by offering reduced rate vat (5% instead of 20%) on heat pumps for domestic use & was taking the UK government to task on this. I guess Brexit put an end to all that. I know you said the power supplies for the outdoor units is being sorted next week but I would be interested to see how they do that. Ideally each outdoor unit should have its own separate power supply with its own circuit breaker fed directly from your consumer unit. Each outdoor unit should also be fitted with a local electrical isolator. Depending on where your consumer unit is (probably in the garage?) that may not be all that easy to achieve as it looks like its on the opposite side of the house to the outdoor units. I had a similar issue in my house so I had the outdoor unit fed from a fused spur teed into an outside wall socket from the ground floor ring main. For airflow reasons the location of the unit in you bedroom is probably a better solution than on the outside wall facing the bed. That said (& assuming you have a loft space), an alternative but more expensive option would have been to consider one or possibly 2 ducted indoor units located in the loft to feed all of the upstairs rooms via supply & return air ducting & ceiling grilles to & from each room. Ducted systems are considerably more expensive to install so totally understandable why you didn't want to consider them as an option. Also, I would be interested to know what those wall brackets are for at 21:50? Looks like they may be to support a Polycarbonate roof perhaps? The reason I ask is because I have a similar 3ft wide dead end walk way on my house where my outdoor unit is & in which I store stuff. A roof over the walk way would be handy & those brackets look they not only support the roofing but can hold a rainwater gutter as well? Looking forward to you next video.

[@TimAndKatsGreenWalk]

That's interesting to hear about the VAT situation. I wonder how long they'll keep that going or if they'll revert back to 5 or 20% any time soon. Still, it was a nice surprise! You're right about the electrical supply. My original assumption was that we'd need a long cable running from the garage, under the front step and then along under the same window as the ducting for the hall unit to the other side of the house where the outside units are. However, when we had an electrician round to take a look he said that as long as the ground floor circuit is 32A (which it is) it would be fine to hook into that by going through to the lounge as you have done. We actually already have a panel on the lounge wall in the perfect spot, designed to take an electric fire place, so we'll use that for the supply. He's going to put a large double socket weather proof box on the outside wall in between the two external units so that there is space enough that I can connect a smart plug to each unit to monitor the energy usage. The external units themselves will then just be connected via a standard 13A plug. That also provides a convenient way to isolate the units for maintenance purposes since you can just turn off the switches. The wall brackets are indeed for a shelter with a polycarbonate roof. I had to take a couple of the roof panels off temporarily so the ducting for the bedroom and hub units could run down the wall. I need to cut a couple of notches in the panels to fit around those ducts before I fit them back on. The whole shelter is my Dad's design and he constructed the brackets and then helped me fit them. And they do indeed include some guttering, which takes the rain water back to the downpipe at the front of the house. That shelter only covers half the wall so the external units are still exposed to ensure that they have enough ventilation still.

[@colingoode3702]

@@TimAndKatsGreenWalk Like all incentives the 0% Vat will disappear at some point. Just like the EV grants did. That said the previous 5% Vat deal was around for quite a while. There has been a huge increase in domestic Air to Air A/C system installations brought about by more people working from home, just like you. Not sure the National Grid likes the situation because it puts more pressure on their aging infrastructure. Your Dad's a bit handy isn't he? And there's me thinking those cantilevered brackets were available online somewhere. The fence next to my side wall isn't mine so I can't hang anything off of it so those brackets would have been ideal for what I need. Never mind I'll find another solution. I've got some GivEnergy Smart Plugs but I can't use them for my heat pump cos it's hard wired in with no plug. Mine's a 4.2/5.4kW Fujitsu Wall mounted system (cooling/heating) which we use for heating mainly with the odd bit of cooling in the summer when needed.

[@bjjcjc]

Many thanks for the video, very informative and I am definitely thinking for our own system of going air to air for heating plus a separate heat pump hot water cylinder . Could I ask a question about what you were advised re the placement of heat pumps? How have you found having the outdoor units in such a condensed area?

[@TimAndKatsGreenWalk]

They've worked pretty well, to be honest, I don't think they've suffered for being in the side passage at all. The outside temperature that they report is always within a degree of what the weather is currently showing so they don't appear to be recirculating the "used" air, as it were. It was actually my suggestion to put them there as it was the most convenient, most out of sight, and furthest from neighbour windows, so as to minimise visual and audio impact, and I was willing to accept a small hit in efficiency for those other benefits. But as I said, I don't think they've suffered in any case, so it all worked out well in the end.

[@pawekropi5077]

Thank you for a very informative material, actually I'm just about to install the very same unit in my house and since it's a fairly new model, there's little info to be found on its real life operaton.

[@TimAndKatsGreenWalk]

No problem. I hope it works well for you!

[@pawekropi5077]

​@@TimAndKatsGreenWalkHi. I was wondering about your experience with these units since I've got some issues and the service say it's normal. 1. When the fan speed is set on 1 or 2, at about 0° outside, max temperature of air getting out of the unit is about 25° so the room temperature does not go above 18-19°. In order to get 40° out of the unit I've got to set the fan speed on 3. It stays hot when back at 2, but after defrost it gets back to 25°. I've put it on AUTO, and the temperature is ok but it gets noisy after defrosts. 2. Defrosts are quite long - about 15-20 minutes, and they occur every 1 or 2 hours. 3. I use time schedules, day temp at 22 and night at 18. During the night the compressor keeps working and taking about 250W, with no air blowing. When it should go up to 22, sometimes nothing happens, and the indoor temperature reported by the app is 21°, whereas the thermometer shows 18°. If I turn it off and on again, the unit starts heating. In my Mitsubishi units upstairs no such things happen - defrost takes about 5 minutes and they blow hot air at all fan speeds. What are your observations?

[@TimAndKatsGreenWalk]

@@pawekropi5077 we tend to use our system in a slightly different way to you so we've not seen quite the same issues, although it does do some odd things from time to time, but generally it's not caused any problems as such. We usually have the system switched off overnight with it scheduled to turn on at 18 deg at 6am, then I usually adjust individual rooms up or down as required during the day, so the office to 19, or the lounge to 20, say. We never use anything other than fan level 1. Then at about 20:30 everything switches off until the following morning. Defrost cycles usually take no more than about 5 mins and so far this year I've only noticed it happening once, although last year when it was super cold for a week or more they were happening every couple of hours. The units do sometimes report very different temperatures to what the room thermometers are saying and I think that's because the internal thermistors aren't ideally situated. If the particular unit isn't currently running the refrigerant is still hot inside the heat exchanger (presumably because it's still being heated for the other units), so the thermistor reads much higher than it should. If we need to trick the unit into starting up again I'll usually add a couple of degrees to the set point in the app and wait for the fan to start up, at which point it usually then starts registering a more accurate temperature because the ambient air is now flowing over the thermistor. Regardless, I don't think we've ever had issues with the air not coming out hot enough. I'd classify these issues as slightly annoying niggles rather than problems but I'd certainly agree that it's not a perfect set and forget system. It does require a bit of manual fiddling occasionally. It's interesting to hear that your Mitsubishi system works differently. I wonder how other systems work in comparison.

[@pawekropi5077]

@@TimAndKatsGreenWalk Thanx for the info. I will mail the Toshiba office and ask their opinion, just wanted to check if any of these happened to other users. Since the Haori is in the living room, this excessive noise is not a big issue, but in a sleeping room this would be a disaster. Actually I was thinking of adding an extra one closer to the couch when we usually spend our evenings, but now I have second thoughts. As for the Mistu units they are from the basic 'Compact' series, no frills at all, but they are super silent except for a short time, maybe 30 sec during defrost, but it's only the compressor outside the building. Haven't seen them work at lower temperatures than -7°, but in this range they are just perfect.

[@lucasjones2250]

Hi Tim, thank you for the great videos, they are very informative. We are also interested in installing an A2A multi split system in our home. One of the rooms to be heated is a similar size to your "hub" room, how do you find heat distribution from the 4.5kW unit in this large room? I can see a smaller room heating up quite uniformly but am concerned a larger room would not heat up as comfortably from just a single unit. Thanks (sorry if you've covered this elsewhere)

[@TimAndKatsGreenWalk]

It's usually fine, occasionally we have to put it on fan level 2 rather than the lowest if it's particularly cold outside.

[@aadeshsiingh8519]

Hi Tim. Very nice Video. just wanted to check which installer did this setup. Thanks

[@TimAndKatsGreenWalk]

Just Chillin' from Stroud. A one guy operation, not sure what his catchment area is though.

[@sweets7737]

Super informative video! I was wondering if air blows out of the indoor units like a fan. If you stand under it, can you feel air blowing on you?

[@TimAndKatsGreenWalk]

Yup, there's a fan that blows the air and you do feel it if you're stood under it. We generally leave the fans on their lowest setting and pointed directly downwards when heating so there is never a noticeable draft. Except for when we walk in and out of the lounge, as the hall unit is over the lounge door.

[@sweets7737]

@@TimAndKatsGreenWalk thank you for explaining! For some reason sources online aren’t super clear if there’s a true blowing of air so I never knew for sure. Thanks again!

[@willhowells1991]

Great video. I'm seriously considering a similar arrangement to heat our stone cottage. Can i ask, did you have to notify the DNO before your install and it so was the Toshiba system on the register database?

[@TimAndKatsGreenWalk]

I didn't initially because our installer said it wasn't required, but after the install I discovered I probably should have, so I did end up contacting the DNO to notify them. They said it was all fine.

[@willhowells1991]

Thank you for replying. I found your video really helpful and has confirmed my decision.

[@contactingrichard]

20:16 Great content. Thank you. I have read that the external units must be at least a metre from a shared boundary. Do you know if this is the case?

[@TimAndKatsGreenWalk]

That's only if you want to avoid planning permission. There are a few criteria for that, including the 1m from a boundary limit, so if any of those are not satisfied you need planning permission. That's all it is.

[@kadmow]

Question, whether a small capacity Air to Water heat-pump could be integrated into the water/boiler - radiator systems, previously installed in the "lesser used areas of the house?? - as air to water (in the UK) is typically less expensive to operate than electric resistance heating.

[@TimAndKatsGreenWalk]

Financially it wouldn't really be worth it as those rooms don't get heated very often at all, so the extra heating cost when we do need to heat them is extremely low already. In fact by leaving the doors open they tend to warm up to a reasonable temperature from the air rising up from the hall unit, so then they only need a small amount of extra heating, if at all, when we have guests (which isn't very often anyway). That's worked well for us so far at least.

[@JeniTehan]

You mentioned a few times keeping the fan speed on the indoor units set to low, have you run them at all on the auto setting? I've got a similar Toshiba system but one outdoor unit with four indoor, installed about two months ago, and I've been running them on auto pretty much all the time. The auto fan speed was recommended by the installer so they can ramp up and down as necessary, and I've read elsewhere that auto is usually recommended as well. The fan noise, indoor and outdoor, goes up and down, too. I'd be interested to know how that works for you, my outdoor unit can certainly get a bit noisy, especially when it's been really cold outside, and I wonder if always keeping the indoor units on low would change that, or affect how much heat is getting in the house. I think it's primarily the highest power Haori unit (RAS-B164KVRG-E) I've got in the living/dining room affecting it most, the other three never really ramp up in the smaller bedrooms.

[@TimAndKatsGreenWalk]

I've occasionally tried them on auto but mostly they seem to stay on the lowest fan anyway, so we decided to leave them on low to prevent them ramping up. If it's taking a while for a room to get up to temperature we sometimes manually increase to fan level two for a bit which works well, but that's usually only for short periods. We did have to do that a bit more when it was super cold outside, mind, so perhaps auto would have been better then.

[@BarryHaegerSalesCoach]

Tim interesting video for sure and I'm balancing the pros and cons myself for a 4 bedroom 1970's home which is well insulated with 5 kW Solar PV and 10 kWh. Having had quotes for both the Wet Air to Water is less expensive even before the £5k BUS Grant probably because I would need to heat all 4 bedrooms as they are unlike your home in regular use. One thing suppride me was how close you had the out side units to the wall of your house. The out door units for the wet systems I've been quoted for required a minimum of between 200 and 300 mm behind them and a metre in front. Also because the position was to be in an alley way like yours but wider i was told ideally the unit should be raised a bit and wall mounted to minimise cold welling and the recirculation of cold air being drawn through the uint a second time on still winter days. Any thoughts on this?

[@TimAndKatsGreenWalk]

Our fence has gaps between the slats so the air circulates pretty well. The gap between the wall and the units is about 90 mm. It certainly doesn't seem to cause cold welling as the temperature reported by the outside units is very similar to what the general outside temperature is. You may find this video interesting: kzbin.info/www/bejne/gmayY3WJe9aKrbssi=lnTotMAvbVdg63Kt

[@jonnysegway7866]

Good video, what was process for choosing an installer please?

[@TimAndKatsGreenWalk]

More or less a Google search for local AC installers. One thing I would recommend though is look for one that is also MCS registered and knows about planning laws and DNO applications. Most AC installers aren't MCS registered (so it may be impossible to find one that is) and often don't know about that other stuff, which is pretty important, so quiz them on it when getting quotes, as that can save you trouble down the line.

[@ACFPlumbingHeatingAndCooling]

If the heat pump allow you could run the refrigerant pipes vertical on the wall and then through the artic and down to the extra two bedrooms you don’t have any unit so far .

[@TimAndKatsGreenWalk]

Technically, yes, you could do that, although the pipe runs might be too far (they specify a maximum length). A better way to do multiple bedrooms from one outdoor unit would be to pair it to one ducted indoor unit in the loft space with ducting pipes running to the ceiling of each bedroom to supply the warm/cool air. In some systems they can be all controlled independently, as if there were separate indoor units for each room, so you could have different temperatures in each (although all would have to be in either heating or cooling mode at the same time since that's dictated by the outdoor unit). I wish I'd known about this before we got our system, although I take it this is a more expensive way to do it compared to what we did, so perhaps we would have ended up with what we have now in any case.

[@2lturbo]

This is how my bedrooms are cooled. All the pipe work including the condensation pipes go up into the loft and across to a single condenser on one side of the building. The max length quoted is often based on the amount of refrigerant shipped with the condenser. Longer pipe runs and runs with many turns require additional refrigerant. The longest single pipe run for me is about 20 meters. I fitted a ducted unit in a previous house myself which was excellent but the quote for it done professionally was roughly double for split as there’s a lot more work. Also plenums (the bits that connect the ducting to the evaporator) are stupidly overpriced - at least £100 each side. The drawback to the multi split is you can’t have heating and cooling at the same time in different rooms (ducted or split). For that you need a 3 pipe solution like the Daikin VRV, which is more complicated and therefore suited to commercial installations or householders with more money than sense.

[@jamesrichards6324]

Hi Tim, noticed you had a similiar units to us. Your RAS-3 9Kw, although we have a RAS-4 9kw also with HaorI. Although typically only run 3x units. We've seen an issue which we've annoyed our installer with, whereby we can't turn on more than 2 units at the same time. If we turn on 3 or 4 *together*, air off temperatures do not rise above 28oC. Staggering / scheduling works with 2x on, turning the others on later. Although the fault seems to be the fan modes on the Haori's. If we turn on 1x unit in Quiet mode, and 2x in Auto - no meaningful heat output in any room. Even 90 minutes later of them running, energy consumption sits mostly idle at around 1kw. The initial ramp up of kwh / heat never occurs. If we flick the unit in 'Quiet' into 'Auto' suddenly heat starts rapidly flowing from all 3x units, within about 60 seconds. Energy consumption only then starts shooting up towards 3kw, before gradually settling down. After 5 minutes, we measure around 48oC coming off the fan coils. We can then maintain that 'air off' heat if required without a problem, and flick units into silent if we choose. It was a total nightmare when we were seeing defrosts every hour or so a few weeks ago. We hadn't figured it out, so had to give up and revert to 2x Haori's on and light a fire. Have you seen any thing like this? Do you often run in modes other than Auto? Many thanks!

[@TimAndKatsGreenWalk]

How weird. We've not seen anything like that, although we never use auto mode, instead using just the lowest fan setting most of the time, and very occasionally fan level 2. I hope you can get to the bottom of it.

[@jamesrichards6324]

@@TimAndKatsGreenWalk Interesting, thats exactly how we operated on Quiet. Until we found this quirk with more than 2 turned on together. Do you typically ramp up all 3x units together in Quiet? Or are you on a schedule. I remember one of your videos you said you just left them at 18oC all day. Cheers.

[@TimAndKatsGreenWalk]

@@jamesrichards6324 they all come on in the morning at 6am at 18deg (fan level 1) and then I adjust the temperature for the individual units ad-hoc as required through the day. Then they all turn off at 20:30. Sometimes I turn individual units off if they overshoot the temperature too much, as they are prone to do occasionally. That seems to work pretty well for us. I don't know if quiet mode is exactly the same as fan level 1, although in practice that seems to be the case, so I stopped using quiet mode and just set the fan level directly.

[@richardaldous6170]

Hi Tim, Could you of had one outside unit to power the five indoor units and what decided you on Toshiba over other makes. I do enjoy your Videos.

[@TimAndKatsGreenWalk]

Yes, if we'd limited the indoor units to the 2.5 kW ones everywhere we could have had a 5-way split from a single outdoor unit. But we needed that extra power for the larger rooms which meant two 3-way outdoor splits worked out better for us. We went with Toshiba because we liked the Haori inside units better than the alternatives.

[@richardaldous6170]

@@TimAndKatsGreenWalk Thankyou for your reply. We have decided to go with the Haori units because of the design and can attach our own material, Picture or even a Cross Stitch!. I have been told by my Installer that they are not available until August or September which is a bit of a pain, but I feel it is worth the wait.

[@castleman7300fx]

Hi, looks a tidy install 👍 We have 2 bed bungalow ! so maybe a little easier to hide some of the services, although I'm not too bothered about seeing trunking. It's all about the end results. Would you be able to provide some details of your installer ? Tia

[@TimAndKatsGreenWalk]

It was a local one-man installer from Stroud called Just Chillin'. Nice chap. Not sure how wide his catchment area is though.

[@castleman7300fx]

@@TimAndKatsGreenWalk Many thanks 👍

[@richardc1983]

Ducted units ideal for a bungalow. Hide units up in loft.

[@lucas4ovwales]

Really good video thanks. Did you need planning permission for having more than 1 outdoor unit? Or for being within 1m of neighbours boundary? I want mine in an alleyway like yours, but it’s less than 1m from the neighbour boundary, so I’ve read that it therefore needs planning permission.

[@TimAndKatsGreenWalk]

Yes, that is a requirement unfortunately.

[@lucas4ovwales]

@@TimAndKatsGreenWalk that's very helpful - thanks for the quick reply. Just watching some of your other videos now. Your setup looks great and I'm definitely sold on the idea of multi-room air conditioning. Mainly for summer cooling, but it looks ideal for some winter heating too (especially with gas being expensive vs off peak electricity). I think I'll just have a unit installed near the back wall. It won't be as neat and tidy as yours down the side, but should serve a good purpose.

[@r3dsouza]

In view of this cold spell we are having in the UK with -5C outside, would be really nice to know how the system is performing in terms of heating the rooms. Also, would be great to know how much energy and peak power is being used. Thanks.

[@TimAndKatsGreenWalk]

Yup, a full report will be forthcoming in a future video, never fear!

[@Barry-xg1rd]

@@TimAndKatsGreenWalk bump

[@TimAndKatsGreenWalk]

@@Barry-xg1rd don't rush me.

[@jorkirasalas2726]

Hi Tim. Not sure if you've got battery storage installed yet? If so has the a2ahp run cost-effectively on off-peak stored energy? Can’t remember you saying anything about overnight running costs/energy usage rates (but my ageing memory isn't so good)

[@TimAndKatsGreenWalk]

No, not yet but soon! My latest spreadsheet video has a bit about combining the heating with batteries and solar will make it considerably cheaper to run, and even results in potentially saving enough in running costs to pay off the install, which I wasn't expecting to be the case.

[@johncolclough625]

thanks great help we are going start building a new 4 bed dwelling, and the layout will be very sililar to yours thanks for that 1 question is there any reason didnt have any loft mounted units with ceiling grills, be good to know as thats the option im thinking about as a new build so abit more flexibility

[@TimAndKatsGreenWalk]

Yes, indeed, in an ideal world I would have gone for that version. However, it is more expensive to install than the wall units, so that's the main compromise. However, if I was building a new house that's what I would go for in the upper floor, for sure (and possibly underfloor heating in the ground floor from a separate system).

[@SarahMould]

I asked my installer about ceiling units. They are designed for commercial installations with (I think) 16" gaps, which are much wider than normal joist spacing in homes.

[@TimAndKatsGreenWalk]

@@SarahMould you can get a unit that sits in the loft space with separate pipes that lead to small vents in the ceiling in separate rooms, you don't need an actual ceiling unit in each room. Those are definitely available for domestic use. Look for ducted systems rather than ceiling cartridges.

[@alandoyle507]

Hi Tim, finding your videos very useful. Looks like the walkways down the side of your house are of similar dimensions to mine. Ideally that would also be where i would place the outside units but i read somwhere, buliding regulations i think, that there should be a separation of at least 1 metre between the unit and the boundary with my neighbour. That doesnt look like its the case in your installation. Have i got that wrong?

[@TimAndKatsGreenWalk]

The 1m from a boundary condition is a planning permission issue rather than building regulations. There are a handful of criteria it has to meet for it to fall under "permitted development" (i.e. no planning permission required) but if the outside unit is closer than 1m to a boundary then that counts as requiring planning permission.

[@alandoyle507]

@@TimAndKatsGreenWalk Many thanks, maybe not such an issue then.

[@billywright1963]

Hi Tim, did your installer quote for a maintenance charge for the Toshiba units in order to satisfy the 7 year warranty?

[@TimAndKatsGreenWalk]

Yeah, I'm getting them serviced annually. The cost depends on the number of indoor and outdoor units but for us it's about £200.

[@neergh8886]

Another airair system here, Mitsubishi split system 2 x 5kW and 2 x 2.5, installed in 2016 so 4 wall units but sized for 5 maximum. Not had any faults and gas is original. Worth getting a Raspberry Pi with Home Assistant so you can use HA to control rather than the apps your usually get Mitsubishi and Toshiba etc. Last east I installed a Steibel Electron storage heater in the hall on Economy 7 not as efficient as ASHP but give you some heat in the middle of the house. Solar panel installed this year which reduce the grid import.

[@TimAndKatsGreenWalk]

Good stuff.

[@richardc1983]

How does the raspberry pie system work? I've an lg multi split system and hate the lg thin q app.

[@Benjamin-dx2wt]

Harry do you have Mithubishi Heavy Industries with Wifi or Mithusbishi electric? What app do you use on your phone to connect to home assistant on your rpi (which I guess still operates the indoor modules via wifi?)

[@neergh8886]

@@Benjamin-dx2wt Mitsubishi Electric ASHP supposed to be better than the heavy industries units. Use the MELCloud app and each wall unit has a WiFi module and then connected to internet router. 6 years old and still working perfectly. Part number for outdoor conditioner MXZ-5E102VA 10.2kW cooling 10.5kW heating.

[@andycampbell193]

Thanks for the vid, really informative. Maybe a naive question, but could you have used 1 heat pump with 5 indoor units rather than 2 units? Would this be cheaper? If not, would love to know the reasons why not. Thanks

[@TimAndKatsGreenWalk]

It's about the total capacity of the indoor units. There are 5 split systems using the same type of outdoor unit but the total capacity wouldn't have been enough to support all five indoor units unfortunately, because of the two higher rates indoor units. Hence the double outdoor units

[@lyracian]

There is a picture of the brochure about 8 minutes in. You can get a pump that takes 5 indoor units but it is only rated at 10 kW. My understanding is that means you either cannot get much from each unit or cannot run them all together if you want a 5 kW unit in the lounge and 3 kW in the hall it fills up quick.

[@TimAndKatsGreenWalk]

@@lyracian Yes, exactly that.

[@andycampbell193]

@@TimAndKatsGreenWalk brill, many thanks👍

[@richardc1983]

Depending on the manufacturer you can get a 5 head indoor unit that has capacity to run all indoors, all will allow you to run at the same time just some may not be able to give full capacity. My LG unit has 5 indoor heads and total output 14kw of the outdoor unit.

[@Benjamin-dx2wt]

Tim, may I ask of your experience with the Toshiba app? I would ask this during your upcoming Q&A but we have to make a decision on our A2A system this week and this is probably the main deciding factor. Is it intuitive? Does it get the job done? E.g can it change all settings, set schedules etc? Thank you very much for your video on the subject it helped us so much deciding to have an A2A system sooner than later.

[@TimAndKatsGreenWalk]

The app is certainly functional but not the most stable. I can use it to set up timers for all the units separately, which is great, although it only has four separate timers so turning on and off twice will use them all up. That's sufficient for us though. When I say it's unstable I mean it tends to crash a lot, so I have to kill it and restart, but that's not a deal breaker, just slightly annoying. You can change every setting using the app and it's much easier than using the remotes so we use the app exclusively. You can also have multiple devices logged in to the same account so Kat can control our system as well from her phone.

[@Benjamin-dx2wt]

@@TimAndKatsGreenWalk That's great Tim thank you. In this case we'll delay our decision until we get a quote from the only Toshiba certified installer we have in our area as before watching your video we were almost ready to pull the trigger on a Daikin or MHI system. Excellent work with the whole chanel btw!

[@TimAndKatsGreenWalk]

@@Benjamin-dx2wt thanks! I'm glad you've found the channel helpful, that was the whole reason for starting it in the first place so I'm happy it's doing what I intended. Good luck with your final decision. I'm sure you'll be pleased with whichever system you end up with.

[@kalelkar]

What is the warranty that comes with this system? Separately, I imagine this would be quite noisy if you had to place against a wall that's underneath your bedrooms because you'd hear it in the summer if you kept the windows open. I guess it works for you as yours is on the side of the house.

[@TimAndKatsGreenWalk]

Placement is important, for sure, but it's not super noisy (as demonstrated). You're unlikely to be running it overnight in Summer anyway. You wouldn't need it for heating and if you needed cooling overnight you wouldn't have your windows open as that'd let the cool air out. The warranty is three years, I think, not 100% sure.

[@judithkitchingman4419]

Could I ask you why you chose the Toshiba rather than any other make? Thanks

[@TimAndKatsGreenWalk]

Kat liked the look of the units, basically.

[@Joe-lb8qn]

in all the videos i've seen on these they are mounted high (and a relatives newly installed is). However i have seen just the one where its mounted much lower, eg where a radiator would be, on the basis that hot air rises and so why start with hot air at the top? After all we dont install water radiators up high so why warm air heaters? Any thoughts?

[@TimAndKatsGreenWalk]

These are designed for cooling primarily, hence mounting up high. But in heating mode with the vents pointing directly down the warm air goes to the floor first before spreading out and rising up, so it works fine that way. Pros and cons, for sure.

[@guygillmore2970]

Thanks for this. Are you single phase and if so, was the DNO okay with two units?

[@TimAndKatsGreenWalk]

I asked our installer about this and he claims that AC units don't require DNO approval, but now you've got me wondering! I've now contacted our DNO for confirmation so I'm interested to see what they say. If we did need DNO approval I'll be very angry with our installer! And yes, we're on single phase with a 100A supply.

[@protectiongeek]

@@TimAndKatsGreenWalk thanks for a great video, Tim. We are planning to install an A2A system next year and although our enquiries are at an early stage, one potential installer recommended the Toshiba system you have, so it was good to see your system in action. As a retired DNO engineer I can safely say that your ASHP installation does not require prior approval by the DNO. That's not to say that there would be significant issues for the DNO if everyone in the street follows your example as it's very likely that the distribution network was designed for whatever method of space and water heating was originally notified to them by the developer. As it's a new-build there is a chance that some thought was given to the use of EVs and maybe heat-pump installations. Occasionally heat pumps have been known to cause issues on the local network due the high starting currents that the motors for compressors and pumps impose for brief periods. This can manifest itself as 'flicker' or 'a dip in the lights'. The modern electronic drives used in the likes of your Toshiba ASHPs greatly reduces these currents so they are less of an issue. The widespread use of LED lighting also ameliorates the effects of these 'dips'. There's no doubt that the increasing use of heat pumps will present a challenge to DNOs so it's not impossible that - for a while at least - DNOs may feel compelled to introduce some form of prior approval in the future while the networks 'catch-up' with the growing demand. I wish you and Kat all the best and look forward to your future videos.

[@TimAndKatsGreenWalk]

@@protectiongeek thanks for the explanation, that's very handy to know. I'm glad you're enjoying the videos.

[@protectiongeek]

@@TimAndKatsGreenWalk hello again. I have to say that I stand corrected on the notification front! After watching your video I've been doing a little research and it looks like the Energy Networks Association have lumped-in heat pumps with EV charging points and their guidance *DOES* suggest that notification to DNOs is required. So, my sincere apologies for inadvertently misleading you! I clearly wasn't as up-to-date with developments as I thought I was. To be honest, I think the DNOs are concerned (not without reason) that the load growth and, perhaps more importantly, the _rate_ of load growth is difficult to keep up with. My brief research also suggests that many DNOs are also struggling to respond to notifications within the required 28 days and are taking 2-3 months to respond. Not surprising given the pitiful staffing levels! It's a bit rich to insist that installers and owners comply with the notification criteria only to fail to meet their own licence obligations. The onus for notification lies on the installer, much as for PV or battery installations. Depending on the ratings of the equipment some installations fall into the 'Apply To Connect' category (so 'permission' from DNO is required), while other (presumably smaller) installations fall into the 'Connect & Notify' category (like a lot of smaller PV installations). More information at the links below - www.energynetworks.org/industry-hub/resource-library/low-carbon-technologies-combined-installation-process-flow-chart.pdf mcscertified.com/wp-content/uploads/2022/01/EVCP-HP-Connections-Form-v3.4-.pdf www.gov.uk/government/publications/register-energy-devices-in-homes-or-small-businesses-guidance-for-device-owners-and-installation-contractors/register-energy-devices-in-homes-or-small-businesses-guidance-for-device-owners-and-installation-contractors

[@TimAndKatsGreenWalk]

@@protectiongeek Thanks for updating me with your research. As it happens I did contact our DNO and they said I probably should have made an application. They're now taking a look to see if the install is ok. My installer was adamant AC didn't require approval but I suspect he's just not fully up to speed. He kept saying "it's only for heat pumps" to which I replied several times "AC is a heat pump!". It's annoying when you can't rely on professionals to guide you properly.

[@Rubbernut]

Excellent video, looking into the same system myself. Can you tell me why you went for two outdoor units instead of one bigger outdoor unit please?

[@TimAndKatsGreenWalk]

One outside unit wouldn't quite provide enough power for all five indoor units, given two of them are the more powerful ones due to the larger rooms. Having said that, we probably could have gotten away with it in practice.

[@Rubbernut]

@@TimAndKatsGreenWalk excellent thank you for the reply

[@Rubbernut]

I’ve watched all you videos and really enjoying the attention to detail, I’m in Leeds and just had a company out to price a 3 split system up, but wanting the flexibility of going up to 5 when I’m ready, just trying to sort things out as I’m wanting to go into the loft and down into 2 bedrooms as they cannot go on the outer wall like you, but worried it will ruin the look of the units, is this the reason you didn’t go into the loft and back down into your other bedrooms

[@TimAndKatsGreenWalk]

@@Rubbernut pipe run length is an issue, there's only so far you can run them from one outdoor unit. Plus when you go up into the loft the condensation pipe goes up, which means you need pumps to suck it out (when operating in cooling mode). We use those other rooms so little that it wasn't worth adding units to them. A better (although more expensive) solution would be one large ducted unit in the loft with ducts running into the ceiling of each bedroom.

[@Rubbernut]

@@TimAndKatsGreenWalk many thanks for the reply again need to give it some serious thought

[@diogenesagogo]

Many thanks for your comprehensive expostulation! Very informative. We're considering a similar system, but I think our heat losses are much smaller; I've calculated approx. 1.7 kW for a 20 deg C temp. difference (house is 140m2 total floor area) & that seems to be working out in practice. This means that we need a much smaller installation, a lot fewer indoor units, & I'm wondering if the heat will distribute OK - do you find that the heat spreads throughout the house pretty well? Thanks again.

[@TimAndKatsGreenWalk]

We tend to keep the doors closed to keep the heat in the smaller rooms, as we have them slightly warmer than the hall. So I'm not really sure if the heat would spread much. If you have quite an open plan space you might find it spreads though. I'd suggest a unit in each room you spend significant time in, and maybe one in the hall. Also worth looking into a ducted system, which can work quite well in the upper floor as you can run the ducting through the loft. I wish we'd looked into that before but didn't realise it was a thing when we chose the wall units for upstairs.

[@diogenesagogo]

@@TimAndKatsGreenWalk Yes, ducting sounds like it could be the answer. Got a guy coming next week to look at possible installations so hopefully he''ll come up with useful suggestions. Pretty well sold on the concept though, there's not really any viable options out here in the sticks.

[@andrewstephens8859]

@@TimAndKatsGreenWalk Great video Tim - because of it I am now seriously considering an A2A system 👍 Wasn't quite sure where to place this but your attempt at zoning seems a reasonable place for my very "average" comment. I assume your 7.5KW heat loss was based on worst case 21C inside set-point/-3C ambient outside which results in 313 Watts/Kelvin thermal conductance. I can't find the specs for your units but for a similar (RAS-3M18G3AVG-TR) the heating capacity is stated as Min 1.9KW (Max is 8.3KW) - the inverter providing modulating capability to the DC twin-rotary compressor. Averaging your 2 units, running at minimum, therefore provides a difference to outside ambient of: (2x1900)/313 = approx 12Kelvin i.e. if your internal set point is at, say, 21C then any ambient outside temp above (21 - 12) = 9C will require your units to on/off short cycle to drop their output below their 1.9K average with an associated compressor start/stop drop in efficiency. Now, if only one outside unit was used then, at min, the difference is 6Kelvin and outside ambient can rise to 14C prior to short-cycling inefficiencies. Averages aside, could it be an interesting test to leave your outside unit (for the 2 upstairs rooms) off all the time, keep all your doors open and see what happens? I tried to read most comments here before posting but couldn't see anything related - did you choose two units (and overpowering) in an attempt to shorten acceptable response time from cold?

[@TimAndKatsGreenWalk]

@@andrewstephens8859 honestly the choice of two heat pumps was simply down to the fact that the rating for each internal unit added up to more than the power output of a single outdoor multi-split unit. In reality I believe we could have gotten away with a single 5-way multi-split system, rather than two 3-ways, and it would result in less cycling, as you say. In fact, if I was to do it again that's what I'd do. It just means that the indoor units would not be able to output their maximum power all at the same time, but I don't think that would be a problem as I don't believe they ever all reach their maximum at the same time in our use case. I know more now than I did when we got the system so at the time I was led by the suggestion of the installer rather than planning it all through myself thoroughly beforehand. Unfortunately we couldn't do your suggestion of turning off the upstairs rooms as one upstairs room is on one external unit and the other room is on the other external unit. The two pumps run the front and back of the house, respectively, not the top and bottom (see the house plan in the video). What I tend to do is turn off all units connected to a given external unit when I see it starting to cycle, and then turn it back on again a few hours later, if required.

[@TimAndKatsGreenWalk]

@@andrewstephens8859 oh, and I showed my heat loss calc in a recent video here: kzbin.info/www/bejne/pXWplnyPhbqNsMksi=UoXMUSS4BbQn20O1

[@kin9225]

Excellent video as usual, I can’t helped but noticed the location of your external compressor units, did you know you have to have planning if it’s less than 1 metre from your neighbours boundary wall/fence. But most just ignore it and simply didn’t know about it. In my case, mine is 0.86 metre away, I wished my installer had told me about the 1 metre rule!

[@TimAndKatsGreenWalk]

Indeed, we do know about that rule but only found out about it after it was installed. I too asked our installer about it at the time and he said there was no need for planning permission. Honestly, I really wish you could actually rely on professionals to know about what's important but sadly you still have to check everything yourself it seems!

[@jablot5054]

Can you apply retrospective

[@TimAndKatsGreenWalk]

@@jablot5054 yes, you can.

[@xdgmail1458]

16:53 What are those Bill Tin wardrobes? Ii cant find them online

[@TimAndKatsGreenWalk]

I don't know, I'm afraid, they came with the house.

[@DigitalPosion]

Simple calculation shows that 9amps can deliver not much more than 2kw. If you have 7kw being drawn it would blow a 13a fuse pretty much immediately.

[@TimAndKatsGreenWalk]

7 kW is the heat requirement, the heat pumps only need a third of that as electricity to generate that amount of heat, so about 2 kW (i.e. about 9 A). The fuses are 13 A, so can easily cope with 9 A current draw.

[@johncockram248]

How do you heat your bathroom and your other 2 bedrooms

[@TimAndKatsGreenWalk]

I cover that in our getting off gas video. But basically it'll be electric radiators, probably (since they're not used much), but for now our en suite is still using the towel rail that heats up when our hot water comes on (also to be replaced with an electric one in due course).

[@johnb7644]

What’s the condensation level like in the house, ie there any ? ,

[@TimAndKatsGreenWalk]

Very low. We also use dehumidifiers when the humidity level rises to help prevent it.

[@jdrecords]

Why did you have the outside units on the ground and not up on the wall?

[@TimAndKatsGreenWalk]

They're hidden behind the fence this way, so are less visible and less audible. And it's a lot easier for maintenance if they're on the ground. They're also really big and heavy which would make installation harder and more expensive to put them up on the wall.

[@photografique]

Why did you pick Toshiba system over say Mitsubishi Panasonic’s etc ?

[@TimAndKatsGreenWalk]

Mostly it came down to the look of the indoor units. I wasn't super bothered either way but Kat rally liked the Haori units and I think they look pretty cool and different to the usual white boxes so was happy with that choice.

[@jamesrichards6324]

Hi Tim, what's your understanding of the warranty situation through your installer? Toshiba appear to offer 5 - 7 years in some circumstances, but it's unclear to myself and installers on how this applies to an end user, if a problem occurs in 6 years time.

[@TimAndKatsGreenWalk]

That's a good question and I have to admit I've not looked into it. I probably should.

[@jamesrichards6324]

@@TimAndKatsGreenWalk thanks Tim, I've been quoted similar to yourself for a 5 way multisplit, wella bit less with a single outdoor unit. But significantly more with another installer, the thing that separates them is the allegedge approved partner warranty status. But even that has opened up a can of worms in itself.

[@TimAndKatsGreenWalk]

@@jamesrichards6324 oof, yeah, I bet. I think generally speaking they're all pretty reliable nowadays so perhaps not too big a deal either way. Still, the peace of mind is nice.

[@danyeo1490]

Hi - Is there a max length of the pipe runs then, making it impossible to add units to the other rooms?

[@TimAndKatsGreenWalk]

Yup, the outdoor units specify a max pipe length (I forget what it is). I think it's down to the fact that the store of refrigerant gas is only so much, and there will inevitably be a loss of efficiency the longer the pipes are as they'll leak a little heat regardless of how good the pipe insulation is.

[@danyeo1490]

​@Tim & Kat's Green Walk Thanks for your reply. Sorry if you covered this and I missed it, but do you know how each indoor unit was wired in? As in just joining into the socket circuits already there, dedicated ring circuit for units or each unit etc. Thanks.

[@TimAndKatsGreenWalk]

@@danyeo1490 the indoor units get their power from the outdoor units and the cables just gets bundled together with the refrigerant lines. The outdoor units are connected to a pair of outdoor sockets connected to the ground floor ring circuit.

[@69sauly]

Never thought of a a2a as an option. But that full install price against a standard air source heat pump is interesting. First question. Is with running cost of that system. That seems to be a lot of kw needed to run. Can you do a vid with that data once you have it. Cheers.

[@TimAndKatsGreenWalk]

Yup, absolutely, all those details will follow in the remaining videos in this series, never fear.

[@colingoode3702]

Tim will no doubt confirm but those kW figure he showed are for cooling / heating capacity, not electrical power consumption.

[@TimAndKatsGreenWalk]

@@colingoode3702 Indeed. So far each outside unit draws about 1 kW maximum, and typically closer to 0.5 kW to keep the house ticking over at a comfortable temperature. It depends how cold it is outside, so it might be a little higher than that deeper into the winter.

[@colingoode3702]

@@TimAndKatsGreenWalk It is important that viewers understand that kW of cooling or heating output capacity are not the same as kW (electricity) of power input. An air to air heat pump will achieve a heating efficiency of around 300 to 350% at an external ambient of around 7c. Meaning that for every 1kW of power input, the heating output will be around 3 to 3.5kW. This is what makes heat pumps so attractive as renewable heating (& cooling) systems.

[@TimAndKatsGreenWalk]

@@colingoode3702 I'll be making that clear in the following videos but yes, it's the whole reason for getting heat pumps!

[@FarObserver]

Did you have to get planning permission for the outdoor units?

[@TimAndKatsGreenWalk]

Yes, because they're closer than 1m from a boundary. The requirements are available to find online if you want to know the full list.

[@mapryan]

Was it difficult to get planning permission?

[@TimAndKatsGreenWalk]

No, it's very tucked away out of sight and is well away from any neighbours' windows.

[@jorkirasalas2726]

Tim, did you need planning permission for those two outside units? Building regulations checks on the installation? And how did you go about finding a good installer?

[@TimAndKatsGreenWalk]

Yes planning permission was required (Google for requirements). No, we didn't get building regs checks done. I just Googled for local AC installers but if I was to do it again I'd look for MCS registered installers of AC systems as most aren't (unlike installers of A2W systems who do tend to be) and you might find it useful to have a MCS certificate later. Also, check with your DNO before installation as we didn't realise we needed to do that and our installer made no mention of it.

[@jorkirasalas2726]

@@TimAndKatsGreenWalk interesting Tim, thank you. Good idea about the MCS aspect, but I dont understand why the DNO needs to be notified though, if the current domestic power consumer unit supports the a2a power requirement.

[@TimAndKatsGreenWalk]

@@jorkirasalas2726 yeah, it's more about letting the DNO know so that as more and more houses get heat pumps installed and the load on the local network increases, they can plan for any necessary upgrades (same with EV charge points).

[@jorkirasalas2726]

@@TimAndKatsGreenWalk ah, that makes sense! So notification rather then request for permission! I’d like to go solar+battery+ a2ahp, but need to budget carefully, and need to get some electrical work sorted first.

[@TimAndKatsGreenWalk]

@@jorkirasalas2726 yup, it's a good combination I think.

[@richardc1983]

Itching to know how you've got on these last few days with the cold spell :)

[@TimAndKatsGreenWalk]

So far so good! We'll be giving a full report soon but the house has been nice and warm. We even did a test day using gas so we could do a proper comparison and although it's hard to be precise it looks like we used about a third the amount of electrical energy as gas for a similar level of heating. So about what we expected. I'd like to do another test on a milder day to get another data point but looks like that will have to wait for a few more days.

[@richardc1983]

@@TimAndKatsGreenWalk great stuff what you been setting overnight and during the day? We're away at moment and forgot to leave ours on. House dropped to 12c!!! It's been on all day working it's nuts off to try get upto 19c and some rooms still not there yet. So much better to leave them ticking over than working flat out or just ends up defrosting all time.

[@TimAndKatsGreenWalk]

@@richardc1983 off for about four hrs overnight until the cheap rate, then on again for that four hours, then off again for another two hours until they come on for the rest of the day. So off for six hours per day. When on we typically set the hall and hub to 17 with the bedroom, office, and lounge at 18. If we need to we'll bump one up to 19. Generally the rooms get to a degree above what we set the units to

[@richardc1983]

@@TimAndKatsGreenWalk sounds like the experimenting is going well. Got to do what works for you both and your home.