Virtual Visit a Heat Pump: Take a tour of my Octopus Energy Heat Pump Installation

[@GaryDoesSolar]

Thanks for making this video, STTG - I'll be looking for a heat pump before long and it's great to see a virtual tour like this, to get a very good idea on all the elements involved and how everything is wired up 👍

[@SpeakToTheGeekTech]

Thanks Gary! I look forward to seeing your heat pump journey unfold on your channel :)

[@jeanh9641]

Thanks, Oliver. I did visit a house with a heat pump under the Nesta scheme. I found it a very valuable experience. I was struck by how comfortable the house was temperature wise. A very comfortable all enveloping heat and surprised by the size of the heat pump. I am also getting £100 off my final Octopus installation bill. I think your video will prove very useful to people who cannot do an in person visit.

[@SpeakToTheGeekTech]

I hope it is, thanks for the feedback

[@Muppetkeeper]

We should start a library of these. I will watch this then try to do something similar with my 4 year old heat pump installation.

[@SpeakToTheGeekTech]

I tried contacting Nesta with a similar idea for those who want to learn more but don't really want to visit in person and this video is intended to get that ball rolling... they didn't reply :(

[@jakeartis955]

I'm having the exact same system installed by octopus just before Christmas in December! I'm super excited as I removed the old back boiler a a year ago (was a very cold winter). I've put fresh plumbing 15mm, electrics and radiators ready for the heat pump. My property has some old solar panels so the heat pump should allow me to get the most out of the energy that's produced 🙌

[@SpeakToTheGeekTech]

Nice, you should have a more efficient system than mine with those wider bore pipes

[@jakeartis955]

@@SpeakToTheGeekTech Fingers crossed 🤞 I've gone crazy on insulating not only 300mm in the loft but also 140mm for the ground floor ceiling. House was constructed in the 50s so drafts were plenty. After the install we'll be working on an AC battery and triple glazing for ultimate energy efficiency.

[@MrWobling]

Thanks - I learned a lot of useful stuff about heatpumps from this video. I had no idea some heatpumps run water in the pipes to the external unit; always assumed it was refrigerant.

[@SpeakToTheGeekTech]

Glad I could help!

[@gsnary8592]

Thank you for the video, always good to watch them, Interesting to see you have a braided flexible hose so you can re pressurise your system. We had our Octopus install in July and have only recently used it for heating. We've needed to bleed the radiators, the pressure has dropped but our install doesn't have the braided hose so we can't re pressure it.

[@SpeakToTheGeekTech]

The braided hose is not supposed to be left in place, it's supposed to be taken off and left on a hook on the wall behind it when not in use and connected just for when you want to increase the pressure. But I'm lazy... and three separate valves would have to fail at the same time for it this to be a problem.

[@gsnary8592]

@@SpeakToTheGeekTech ta very much, I'll have to have a look for it!

[@Gazmaz]

Nice and clear and a good explanation 👍🏼

[@SpeakToTheGeekTech]

Thank you, I hope it was useful.

[@Deanus3110]

Your Octopus install looks so much cleaner than ours, ignoring the fact you have it spread out nicely on a wall and not in an airing cupboard / loft. Mainly the external insulation looks very shoddy by comparison. Seems to function at least, got it in July and fingers crossed for winter.

[@SpeakToTheGeekTech]

You can't see in this video, but the tape used to hold the external insulation together had weathered and was no longer very adhesive. Octopus have since been back and sorted this using new extra-water-resistant tape. Still looks just as neat though.

[@Deanus3110]

@@SpeakToTheGeekTech Good to know, thank you. Just looks like standard black duct tape wrapped all round mine for now.

[@AllElectricLiving]

Is the little box your weather compensation sensor or external thermastat

[@fazkhan8009]

Is Cosy 6 replacing the conventional heat pump ?

[@SpeakToTheGeekTech]

Not to my knowledge yet, it’s an option though but not suitable for every scenario at the moment.

[@TypeRhino]

Hello have you found a way of getting your givenergy battery and heat pump to link with agile. The goal being that it can charge the battery twice a day when prices are cheaper. Once in the early hours in the morning and then in the afternoon when prices are low. To achieve this automatically rather than going into the givenergy app remote control section and settingthe charge times. I hope this makes sense. I have talked to givenergy they say the system is agile compatible but int reality you need to go into remote control and set it there.

[@SpeakToTheGeekTech]

I don't personally like Agile, I consider it over-complicated for the majority of users and unless you are very technically minded it's difficult to easily save money. You may have noticed that I actively avoid Agile in all of my guides because it leads to too many question :) There are many approaches though. There's the built-in options which I admit are not great as you have found, or there's jumped to Home Assistant and using something called predbat to co-ordinate your cheap slots. Or... you can just run as normal, heating your home whenever you think is best and convenient, maybe avoiding the known peak periods, and hope that the average unit cost is lower than the standard rate. Agile can be great, but if you have to ask questions about how best get it working then it may not be for you because the questions are only going to get harder the further down the rabbit hole you go, sorry :) Predbat is the way to go for Agile charging your battery the cheapest way possible... but don't say I didn't warn you :)

[@JonathanTracey]

Which Shelly device did you use, I’m getting the same model heat pump in a few weeks and would like to add a Shelly

[@SpeakToTheGeekTech]

Shelly Pro EM 50A

[@JonathanTracey]

@@SpeakToTheGeekTech perfect thanks

[@chrisholland4952]

Could some explain why do you need TVRs if they should be left fully open. Still building up my knowledge base so would welcome some advice.

[@SpeakToTheGeekTech]

Honestly I don’t think anyone really knows. It appears to be a leftover requirement in the MCS guidelines that Octopus have to adhere to in order to meet the criteria for the installation to qualify for the government grant. I imagine MCS will slowly evolve the requirements as best practice changes.

[@RichardASlack]

Probably the same reason a gas boiler is better on an EPC than a heat pump!! “Heating by electricity” was traditionally less efficient than heating by gas. TRVs are about saving waste by controlling the heating in different rooms but are not beneficial when using a heat pump.

[@DavidBond668]

I looked to get a heat pump from Octopus in my home in Scotland. Turns out they don't do Scotland installation. 😢 Nice to see your heatpump tour. Will consider getting one next. I got my solar panels recently. 🎉

[@SpeakToTheGeekTech]

They are expanding slowly across the UK. Speaking with someone from Octopus earlier this year, they tell me they are reluctant to do installs too far away from their support bases because they just can't offer the expected level of aftercare otherwise. The bigger they get, the wider they can spread themselves though so hopefully they'll reach Scotland eventually. I was one of the first installs in Wales and they tend to send engineers from Bristol.

[@afaulconbridge]

Is the mystery box on the wall a weather sensor, to measure outside temperature and humidity so the heating system can compensate automatically (e.g. hotter temps on colder days, cooler and more efficient temps when its only chilly outsider)

[@SpeakToTheGeekTech]

I think the only way to solve the mystery is to open it up!

[@5amonline699]

@@SpeakToTheGeekTech I concur, it looks like a weather compensation sensor to me. Used for offsetting the heating cycle according to outdoor temperature fluctuation. But why is it installed in the garage - even if your garage isn’t heated? Still, should really be external, but not on a south-facing wall I believe.

[@HarjDool]

Thanks will be using you referral code on my Octopus install. Have you had any issues at externals temps below 3 degrees? Some folks on openenergymonitor have said that the Diakin's dont operate well under 3 degrees C? Also is the Shelley essential? Does the Diakin cloud service not provide energy consumption data?

[@SpeakToTheGeekTech]

Thank you! Absolutely no issues concerning temperatures and performance and we did have a few weeks of negative temperatures last winter. The Daikin Onecta app does give you some energy consumption data but I don't find it that reliable - the Shelly gives me much better data and lets me use it in Home Assistant. If you're not fussed about Home Assistant then see how you get on with what's in the app.

[@HarjDool]

@@SpeakToTheGeekTech thanks so much, just waiting for the install date now. I have Home Assistant set up but not sure if I can easily put in a Shelly myself. Is there an integration which gives better data from the HP directly in HA, without installing extra modules etc?

[@SpeakToTheGeekTech]

@@HarjDool There is a Daikin Onecta integration (github.com/jwillemsen/daikin_onecta ) which will give you the same energy usage data that you see in the app (daily/weekly/yearky) but I use it for system control only.

[@HarjDool]

@@SpeakToTheGeekTech can you check your referral code. Octopus are saying that it is not recognised.

[@SpeakToTheGeekTech]

@@HarjDool It should be accepted and it has worked at least once in the past, but I have contacted them to find out what's happening and will get back to you.

[@bazcurtis178]

We have the same issue with the gas hob. Will be interested to know what you swap to. Are you likely to go induction? We only recently found out that the hole under the gas hob is actually smaller than the hob itself. We were worried we would need a new counter top. Turns out looks like we won’t.

[@SpeakToTheGeekTech]

Definitely going to be induction, but how long it will be until we replace it depends on the advertising revenue from this video :)

[@sp1es]

@@SpeakToTheGeekTech I have swapped my hob in advance of the heatpump install, when they have finished they can take the gas meter away :)

[@snecklifter]

I replaced our gas hob with a Bosch 13A induction so just plug into a regular socket. It has 4 rings and we are a family of four. Works absolutely fine for our requirements. Side benefits are a completely flat surface and much better air quality.

[@sp1es]

@@snecklifter I have a 32a circuit for the cooker so I put in a full power hob as you're never likely to have all 4 hobs on full power and the oven at the same time

[@chrisfairbrother9197]

If you remove the gas hob and then the gas smart meter, do you still have to pay a gas standing charge? I know someone who went off-grid and still had to pay an electric standing charge to “maintain the existing electricity supply cable”

[@SpeakToTheGeekTech]

If you have your gas meter removed, all standing charges also stop.

[@edc1569]

Yeah you will ruin your property value if you don’t maintain your electrical connection as reestablishing it later can cost thousands. Just export a bit of solar in the summer and it’ll cover the cost and in the winter it’s a pretty good value supply of last resort.

[@Ben-gm9lo]

@@SpeakToTheGeekTech Just in case your 'all standing charges' gets misconstrued; all gas standing charges will stop if you remove the gas meter. You will still have to pay your electrical standing charge if you are electrically connected.

[@nigelcharles511]

​It is very difficult to go totally off-grid in the middle of winter and for most people practically impossible if you have an EV and/or use a heat pump. It is just annoying that they have increased the daily charge so much.

[@davidcoates6768]

Great video, made me laugh a few times at the start! There are lots of stats videos on KZbin, but not as many looking at the bits installed, like this vid. It'd be nice to see a quick thermal camera walk around tour of it in winter, once we get below 0.

[@SpeakToTheGeekTech]

Maybe I’ll do that. It’s just a pain because it means I have to tidy the whole house and not just those small fixed areas I’m showing you in this one! Have a look at my Topdon video which does a bit of a walk around.

[@davidcoates6768]

@@SpeakToTheGeekTech If it means tidying, then pics of the rads and plant rooms would do. I think I saw the topdon one. Be interesting to see if they hit the designed temp, or slightly over / under due to piping or other factors like leaky windows. Have you had to restrict the flow to ones where the rad was oversized? Or is it just working well because of the heat loss survey? Cheers.

[@SpeakToTheGeekTech]

I opted to upgrade the radiators in the bedrooms to larger ones which output more heat than their original design. I have therefore used the TRVs to restrict the output in those rooms a little bit but everywhere at least hits the design temp if not exceed it at times.

[@ma9mwah]

Do you have the measurements of the footprint of the ASHP including the soak away?

[@SpeakToTheGeekTech]

The footprint of the soak away is 80cm x 147cm

[@tonyt7402]

Is there a condensation pipe feeding the soakaway? I was wondering if you could collect the water in summer for garden watering?

[@SpeakToTheGeekTech]

@@tonyt7402 No, it drips straight off the condenser. You could get an optional drain kit if you wanted which is designed to catch it and divert to a drain, but that's not included as standard.

[@DanielWhelan]

Hi tech twin. I've got the same unit, interested how it performs over winter. Are you thinking of getting a ESPAltherma to calculate cop on ha? I've thought about wrapping it or spray painting the fan over to make it appear less ugly. My install was a nightmare because the engineers were baffled by the mixergy hot water cylinder. 4 months later and they are still trying to resolve the hot water module randomly turning off. Thankfully I've ha automations to auto flick it on

[@SpeakToTheGeekTech]

I have ESPAltherma in there already, mentioned in a couple of other videos but I haven't made one specifically about it yet. I considered the Mixergy but I think for our household the extra expense and complication was just not worth it. Our hot water costs are basically a rounding error in the grand scheme of heating costs! The basic hot water tank works very well for us.

[@DanielWhelan]

Yeah, the it made more sense when we thought we'd have gas got a long time. I don't blame you for keeping away. Mixergy recommended best usage is full the tank go 100% with a ashp

[@jeanh9641]

I rang Mixergy to ask for advice about fitting ASHP and I was told to keep hot water at 100%. I think you lose the functionality of the Mixergy tank.

[@RichardASlack]

@@SpeakToTheGeekTecha video on ESPAltherma would be welcome. We are getting the 4kW unit but I guess it will be the same.

[@paddymcgillicuddy9181]

Hi Oliver. Thanks for the tour. That black box is just a standard junction box. I assume it is branching off to your outdoor temperature sensor? (Required for weather compensation to work properly)

[@SpeakToTheGeekTech]

I think the only solution here is for me to isolate the power and open that box up to have a look!

[@paddymcgillicuddy9181]

Everyone loves a mystery 😄

[@gpbeck]

Frost stat?

[@Fayrewood]

Oliver, great videos as ever! My father in law has microbore pipes too & is considering an Octopus ASHP. Do you feel that leaving them in place and not replacing outweighed the small loss in efficiency?

[@SpeakToTheGeekTech]

With my 10mm microbore system (which has wider feed pipes which the microbore branches off from) then yes, I absolutely feel I made the correct choice. If it had been summer and we were planning to do a massive redecoration of the house anyway then new pipes would have been a no-brainer. It really depends on your personal scenario but I don't reckon it was worth the extra cost and disruption in my case.

[@muckychimney]

Just a wee point, on the filling loop BOTH valves should be isolated when not in use not just one as seen in your video 👍

[@SpeakToTheGeekTech]

Yeah, I'm supposed to remove that flexi pipe and close all three valves. Usually I leave the pipe connected for convenience and turn off all the valves - I admit they weren't all off in the video because I'd just increased the pressure before filming!

[@gpbeck]

Both those filler valves should be closed. In fact legally the hose should be detached for water regs, though few bother.

[@SpeakToTheGeekTech]

Yeah I know :) There's actually a hook on the wall behind where I'm supposed to hang it when not in use! I normally leave all three of the valves shut when not in use, but I had added a bit to the system just before filming and forgot to close them all due to being distracted :) All three valves currently off, but the hose is left there out of pure laziness.

[@nigelcharles511]

A very interesting and well presented video. I would like to change from my existing oil fired central heating system to a heat pump but at present it is difficult to see how it will save me enough for me to break even within a meaningful time period. The current price of oil is about 65p/litre. Allowing for boiler efficiency (about 90% on my condensing boiler) and that there are about 10kwh in each litre of oil, I reckon I am getting energy at about 7.5p/kwh. Typical electricity tariffs are around 30p/kwh peak and 8p/kwh off-peak. Given that the off-peak time is typically only 6h/day and that the heat pumps schedule needs to be able to run most of the day, the average price/kwh used by the heavy pump daily is likely to be around 20p/kwh. Even with a COP of 4 this still equates to 5p/kwh of useful heat. That's a saving of 2.5p/kwh. I use about 1000 litres of oil/year (about 10,000kwh). So my saving would be about £250/year. Even with a grant and assuming my net costs to include a new water tank, several new radiators and plumbing modifications, it would still cost me around £7500 to install a heat pump. This equates to a 30 years break even point!

[@SpeakToTheGeekTech]

You should never think about it as breaking even, that's not what it's designed to do. If compared to gas, it's about cost comparative to run at standard rates. If you need to replace your heating system, put a heat pump in instead. If you want to reduce your carbon footprint, put a heat pump in instead. But if you want to save money, maybe invest in solar panels and a battery. A heat pump is for heating your home, not earning you a payback, it's the wrong way to look at it.

[@nigelcharles511]

I take your point totally. Despite the fact that my house is thatched and therefore cannot take solar panels, through lateral thinking I have a lot of solar and batteries. At home I have 21 panels distributed around my property. At a separate off-grid location 1 mile from home I have another 66 panels feeding 52Ahr usable storage. On top of that I have two camping sized trailers each with 30Ah LFP batteries which take energy home. This all keeps two EVs and the house (minus heating) going for about 10 months of the year. At this time of year my electricity statements are about £17/​month of which £15 is the daily charge. My oil boiler is only 5 years old so no need for a change for at least a decade. It is just a shame that it is uneconomic and probably not green for me to change to a heat pump. @@SpeakToTheGeekTech

[@MCSMIK]

Is it possible to use tado valves with the heat pump? If not, how do you make temperatures even in rooms which are colder? We have a room above the garage and until we fitted tado we had to overheat the other room where the thermostat was in to keep the room above the garage warm enough. Tado 100% fixed that problem. Now we’re on a journey to have the octopus heat pump fitted… I’m a little concerned

[@SpeakToTheGeekTech]

It is possible, but you shouldn't do that. You should size the radiator in that room in accordance with the heat loss for that room. Having an even temperature throughout your home is all about sizing the radiators correctly and making sure they are balanced properly.

[@RichardASlack]

A positive with a heat pump is that you don’t need any smart controls. As Oliver has commented, the system will (or should be) sized to match the heat output of your radiators to the heat loss in each room. If a specific room is getting a bit too warm then a standard TRV can be notched-down a little bit but, if the system is well designed then this shouldn’t be necessary. I believe they actually work best in more open-plan layouts as there won’t be got and cold spots as the temperature evens out. Watch some of the Heat Geeks videos for information on control and zoning (NOT!) Anyone want to buy a second hand Tado system with 9 radiator valve controllers?

[@gpbeck]

System should be balanced so each room heats correctly using the lock shield valves on the radiators.

[@chrisholland4952]

How are you getting on with the heat pump? I have real problems with Octopus. I desperately want their heat pump service but they have assessed that I need a 9kwh heat pump where my house is slightly smaller than yours has 12 radiators, has an B ECB They estimate I will use 12000kwh a year which is a very good estimate, yet the 9kwh pump is based on a usage of 26000 kWh. I have used the rule of thumb calculation which comes out just under 5 kWh. I have asked them how they came to their figures and resent their heat calculations, adding that they must be right as they based 3500 instillations over 28 months.

[@SpeakToTheGeekTech]

I'm getting on brilliantly with it. Have you watched all of my other videos on the build-up to the installation? I got over the system design and my home layout. Built in about 2001, 110m2 floor space, 4 bedrooms. The heat pump sizing was somewhere between a 4 and a 6kW one with the heat loss for my home at 3.9-5kW. They will give you a break-down room by room of the heat loss in your home and the total dictates the size of the heat pump required. That should be where you start if you're looking to question their logic. Have you have the heat loss survey done? It was a £500 fully refundable deposit when I did it.

[@chrisholland4952]

@@SpeakToTheGeekTech Yes, I have relied on your input / video’s and others to build up my knowledge of getting a heat pump. I live in Newport, so like you Cardiff was used for some of the stats like you. My house is 1938 semi but has cavity wall insulation, modern double glazing, insulation under the wooden floors, 3 beds plus office, family bathroom and shower room. I still don’t think Octopus are even close with their calculations, now looking else where..

[@dukeatreides7872]

I have a quote from Octopus for the same unit, the one thing holding me back is I have an EV and Intelligent Octopus so it's 7p per kwH overnight, but this wouldn't work with a heat pump as that's exactly the time I don't want to heat my home, unless I'm missing something? Nice video, thanks for sharing.

[@SpeakToTheGeekTech]

Aha you are in a tricky situation of which tariff is best for the kit you have got! I think you will be fine - your peak rates are going to get used, but remember your heat pump will be at least 3 times as efficient as gas, if not more, meaning even at peak rates it will not cost you more to run. But you can boost your home off-peak and store heat in it like a battery. Tim from Tim & Kat made a video on this if you want the science behind it! (kzbin.info/www/bejne/p2LXinabo92VaK8si=dFqHtt0_s1rSTzwt ). If you really want to reduce your monthly bills though, a home battery is the only option. Charge it off-peak, your heat pump can use it during the day. This is what I do. I think you have the right tariff though overall especially because of the EV which I suspect will use a lot more energy than your heating.

[@tarkadahl1985]

I'm on IOG, have a 10kW ashp and 15kWh batteries. I managed last winter 99.7% on offpeak elec as I was "creative" in my timing for plugging the car in. I topped the batteries up midday most days. Working from home benefit 👍

[@RichardASlack]

It is important to remember as well that, whilst a gas boiler is typically turned off over night (unless it’s really cold), the heat pump tends to run 24 hours with, perhaps a setback of a couple of degrees. This means that the fabric of the house remains warm and the heat pump is just topping-up the heat that is lost. This is why the heat loss survey is so vitally important. Every room has a radiator that is sized to maintain the desired temperature by replacing just the heat lost to the outside. A temperature sensor in the house feeds back into the system but the external sensor is what does most of the work as the level of heating is set according to the outside temperature so that the heat lost is replaced. I think my surveyor was surprised by how much I knew but I do like to be informed!!

[@dukeatreides7872]

That video on the "thermal coasting" was very good, although this may not work with the Daikin as it does not come with individual room sensors to switch off the heating in the bedrooms overnight, but could work with the new Cosy 6. For it to be really worthwhile to get a heat pump and an EV at this stage, seems that either I should invest in a decent home battery such as the Tesla Powerwall 3, or Givenergy and make use of the overnight rates to charge up the battery, or Octopus are missing a more suitable tariff in their portfolio in-between Cosy and Intelligent Go aimed at both heat pump owners and EV users.

[@aidandillon9520]

Really interesting 😊

[@SpeakToTheGeekTech]

Glad you think so!

[@jenksfzr600r]

Thanks for the vlog . Been watching all your heat pump videos as ive just had the install date through of the 14 th of oct for a cosy 6. To go with solar battery and an ev that i already have. I to will only have the gas hob after installation so will be interested to see what induction hob u will install. Im assuming induction of course. .

[@SpeakToTheGeekTech]

It will be induction, but because I have an electric Rangemaster with gas hob built in, it'll be quite expensive to replace! Saving up though...

[@jenksfzr600r]

@@SpeakToTheGeekTech well I did contemplate converting my gas hob to run on the large 48kg bottled gas as. I reckon one of those would last a very long time for just cooking with. It would be an easy install for my hob too and could keep the bottle outside and secured. Then I don't have all my eggs in one basket sort of speak. Was just an idea though .

[@David-bl1bt]

​@@jenksfzr600rnot a bad idea👍

[@marklewisduncombe]

Nice one Oliver.👍

[@SpeakToTheGeekTech]

Thank you!

[@marklewisduncombe]

​@@SpeakToTheGeekTech my install has just been brought forward from mid December to mid October. Will see if they will let me use your referral code for the install.

[@SpeakToTheGeekTech]

​@@marklewisduncombe Nice! Should be a lot more comfortable for you without heating for a few days than having it done in December so that's a massive bonus for you. And I hope so with the referral code, all uses of it are very much appreciated thank you :)

[@digitalfantazia3953]

That box will be related to connecting to external air temp sensor... which should be north facing in the shade.

[@SpeakToTheGeekTech]

That seems to be a common answer in the comments. I guess it’s possibly unused in my installation then

[@digitalfantazia3953]

@SpeakToTheGeekTech when my 9kw was fitted by octopus the engineer said there was an air temp sensor on the back of the monoblock unit in a little plastic housing. As I'm using espaltherma, like you, i suggested they install the remote external one supplied (they werent intending to even though it was sent) ...so I persuaded them :) so I could get a more accurate reading out of the sun. It seems octopus send a load of standard kit to every job which may or may not get used. Then a trip to screwfix if they need extra stuff...Eg they didn't use the metal box isolator inside as they decided to put the proteus plastic breaker on the internal garage wall anyway as it was a back to back install...meaning tank was in garage directly adjacent to heatpump outside. I put a Shelly pro in with it too with breaker for better ashp and legionnaires tank power measurement for the espaltherma.

[@Leo99929]

The heat pump requires a minimum free volume of water to do a defrost cycle. For Vaillant I think it's 15L? So if you have TRV's on your radiators, microbore pipe, and/or a small central heating system, then it can have less than 15L available at some times and that can cause issues for the heat pump. My 3 Bed house doesn't need one as long as I don't use TRV's and my radiators are appropriately sized relative to each other and the heat demands of the rooms they're in. Generally, rather than doing the maths to see if it's necessary, or designing the system so that TRV's aren't required, they just shove a 20L volumizer in and then they're certain they'll have no issues with the heat pump defrost. At the cost of reduced SCOP, increased running costs, and increased installation costs. But they're problems for the customer, not the fitter, and most customers don't know this, so they get away with it most of the time. It's generally a good rule of thumb that if they assume you need a volumizer they aren't doing a "proper" thorough system design and installation for you. More a generic one size fits all. Quite often they can just replace a length of the central heating pipe with a wider diameter and that's enough to get the required volume... Or there's also an electric heating element in the heat pump that can be used for defrost, but that uses more power since it can't leverage the system COP.

[@SpeakToTheGeekTech]

So Octopus have a centralised design team who produce the system designs for the customers, rather than it being done by the installers. The approach from Octopus is a boiler-plate one, so they pick from a number of set designs and tweak slightly as needed. This helps them keep the costs down and customers (like me) end up with a good solution at a great price. But, of course, if you want something much more customised and perfect then a Heat Geek installation is the way to go, and you'll potentially pay the premium that might entail.

[@Leo99929]

@@SpeakToTheGeekTech If you don't mind me asking, how much was the Octopus installation in the end? I'm curious, because they claim "from £500" but I've only heard of ~£5k kind of installed system costs to customer.

[@SpeakToTheGeekTech]

You're in the right ballpark but it's not that simple - mine was a reasonably large install and there are lots of other costs and things to consider. A very modern but small house with perfect pipework and radiators could easily fall into the £500 category, I have heard of a couple of quotes in that region. I made a video covering the full breakdown of costs for my installation: kzbin.info/www/bejne/ipTCZoaioLOen80

[@darrenadams2640]

MCS required TRVs to be fitted but you then just override them by always leaving them fully open? That does not make any sense. How else do you control individual room temps? Also, not sure why you said your tank would not fit into you "half height" airing cupboard - it looks like its full hight to me?

[@SpeakToTheGeekTech]

You don’t control individual room temps, the radiators are each sized to provide a particular temperature at a given design flow temperature based on the heat loss of the room. The skill of the system designer is far more important with a heat pump than with a gas boiler which is why you have to be so careful choosing an installation company. And the airing cupboard is half height, the floor is waist level! The tank is too physically tall to fit in there. Also you’re not allowed to fit water tanks above stairs anymore under building regs I’ve been told, although I’ve not seen that in writing anywhere.

[@markwhittington6409]

That’s your outdoor temperature sensor should be outside on a north wall

[@SpeakToTheGeekTech]

That's what I thought! Except that I'm getting an accurate external temperature out of the system which I assume must be from a sensor in the heat pump itself which matches other external sensors I have nearby, and those doesn't match the temperature readings from sensors in the garage! I can only assume the sensor was wired up but disabled in the setup of the system or something if it is what you're suggesting! A bit of a puzzle

[@philipbroggio9315]

​​​@@SpeakToTheGeekTechI have a 7kW Daikin Altherma 2 which was installed by Octopus in June 22. I had an external sensor installed on a north facing wall of garage low down behind a fence to shade from any solar gain. The heat pump is west facing and at times when ambient is 17/18 and sun is out the temperature goes crazy up to 35⁰c etc. The setting to enable the external temperature sensor is part of the installer setup. The annoying thing is when I use Home Assistant integration for Daikin it only reports the temperature in heat pump. Fortunately having checked spot readings the system is using the external sensor and correctly adjusting flow temp . In Home assistant I plot the AccuWeather temperature. Hoping to install an open energy monitor system soon to complete my monitoring as energy readings can only be taken from my controller manually.

[@markwhittington6409]

@@SpeakToTheGeekTech I assume your heatpump is north facing so is using its internal sensor , still weird that they then bothered to wire an external sensor in a garage then disable it. I would certainly query it with octopus to see was they say.

[@alandwells]

Could be for frost protection internally so that the internal pipework is protected, although I would have thought that there would be sensors on the pipework already and a sensor built into the MMI?

[@johnp-e9963]

I was told the volumiser was there to be a store of hot water when the outside unit wanted to defrost

[@SpeakToTheGeekTech]

That could well be true! I'm just an end user not an expert in this so I can only go by what the heating gurus tell me. I think it must serve a number of purposes though.

[@McOw123]

Yes, it’s there to ensure there’s enough volume in the system for the defrost cycle. The defrost cycle takes hot water from inside and so if there’s not enough volume in the system, you end up in a “death spiral” where the defrost cycle robs heat from the house and yet still can’t quite get up to temperature. We have the same due to 10mm microbore upstairs and the UFH downstairs is sub-optimally spaced out. Also helps reduce cycling due to more volume of water in the system to deal with

[@mickthompson90]

Hi tried to use your referral code they told me that was an account number not a referral, can you provide a referral code please for our mutual benefit

[@SpeakToTheGeekTech]

Hi. It is my account number, and they have accepted it for other customer quotes a few times already. For some reason in the last few weeks it appears certain salespeople there are not accepting it... I've no idea why, it's what they told me to hand out! They have also given me this reference as a workaround: 7319976390 but I have no idea if that works. If you could let me know if they accept that then I'd be very grateful to know! Thank you.

[@kev2020-z9s]

Why copper pipes why not plastic?

[@SpeakToTheGeekTech]

Why plastic pipes and not the longer lasting, stronger, less likely to leak copper pipes?

[@sp1es]

Internal diameter of plastic pipes is typically narrower than copper and when you add connections things get even worse

[@edwardpickering9006]

Octopus quoted me for an install on 8mm plastic microbore, which they said was Ok as long as the pipe had the word "Barrier" on it. In the end didn't go ahead as their "one size fits all" approach would have meant ripping our new build house apart! Also they were insisting that MCS regs meant new hot water tank had to be replaced... Very frustrating... Off to see if my local Heat Geek can come up with a better solution!

[@SpeakToTheGeekTech]

Yeah, Octopus are targeting the easy-install majority and doing is exactly by-the-book. If you need more custom designed solutions then Heat Geeks are definitely the way forward. I hope you get it all sorted. Your hot water tank probably will need to be replaced unless you take a drop in capacity... and that might make it tricky to get the BUS grant.

[@waqasahmed939]

​@@SpeakToTheGeekTechThe guy I'm looking at *isn't* a heat geek BUT he's got decent SCOPs on the "heatpumpmonitor" website. He's relatively local to me so I'd use him This being said, I'll probably be doing it piece meal with ufh installation wherever. It isn't a "need" but I figure given I've got microbore piping and I'd need to replace them anyway, why not get ufh instead?

[@MentalLentil-ev9jr]

Unless your hot water tank is designed for a heat pump, it is likely to need to be replaced. Heat pumps need larger coils inside the tank than is the case for gas. You are likely to get a better install with your local Heat Geek, but it will almost certainly cost a lot more. I had an installation by a local Heat Geek qualified, and it was very expensive. However my existing system was very old with single panel radiators that were often in the wrong place and some rooms never had a radiator - if I'd gone to a new condensing gas boiler I'd have had similar work done.

[@edwardpickering9006]

@MentalLentil-ev9jr Been running the hot water tank off the gas boiler with a flow temp of 45degrees and it's fine. I actually use low rate electricity most of the time. It just very frustrating that MCS doesn't take things like this into account!

[@MentalLentil-ev9jr]

@@edwardpickering9006 That certainly shows that it would work for you if it's ok now with a flow of 45º, it would be a pain if MCS won't allow that. What temperature does it heat the hot water to? I find for my shower that I need about 44º, I run the heat pump hot water overnight and let it get to 47º, it'll drop to 44º by the time we use it in the evening, obviously the temperature needed will vary according to shower characteristics.

[@datoon83]

Buffers/volumisers reduce efficiency

[@SpeakToTheGeekTech]

Yes, in isolation, but if it reduces heat pump cycling then that overall improves efficiency.