Turn your heat pump off when on holiday

[@GrahamSnelson]

Hi, I ordered a new heat pump yesterday after watching a billion videos and liking and subscribing to them all, and now with your constant badgering 😂 I’ve broken my duck and left you a comment! Seriously though your videos, research and experience is much appreciated, thanks pal

[@UpsideDownFork]

Excellent! Glad it's helping

[@Btnboy]

I think a 'billion 'is a bit on the light. to get a good idea..

[@TimothyHarrisonHarry]

Much depends on on the thermal mass of your house. Ours is a 1950s brick and concrete block building with concrete internal partitions too, so the thermal mass is super dominant. I turned the system off on our first holiday a couple of years ago, and never again!! Now I just set it back a couple of degrees, and ramp it up again a minimum of 48 hours before returning. We love our thermal mass!

[@UpsideDownFork]

Yes! Very true and I wish I had mentioned that in the video!

[@andrewcoles4271]

Great video! I've ran a few scenarios through a simulation to see if there's a way to make it pay off, and get the same sort of results you're seeing (which is always reassuring). In summary: - If you're away in mild weather it's barely worth it. I'm developing an AI heating controller, and it did respectably; but it would take someone as dedicated as yourself to make it pay off by hand. - If you're away for a week in freezing temperatures, it actually could save you a few quid, without needing to be too clever about it. (if it's -2 outside, the heat loss is much lower at 10 degrees inside than 21; the flow temperature can drop; etc. This comfortably pays for the reheat before you get home, even if the reheat is a bit clumsy.) - In both cases, a rule of thumb for best pay-off is to start reheating about 36 hours before you get home; and gradually ramp up the target temperature in line with periods of cheaper electricity.

[@UpsideDownFork]

@@andrewcoles4271 great stuff! Thanks for sharing 👍

[@johnbarleycorn7845]

Got a Mastertherm ground source heat pump, full weather compensation, no room stats. Underfloor heating downstairs, rads on 22mm pipework upstairs. Turned h pump off a week ago and set heat curve to 30°. Monitored flow temp via app during absence. 2 days before returning turned curve back up to 37 then 38°C. Got in last night and thermometer was reading 22°C - happy with that.

[@UpsideDownFork]

Nicely done!

[@FRZ5951]

Yes, thermal mass is your friend when temps are dropping, but your foe when you want the (internal) temp increased.

[@UpsideDownFork]

So true!

[@v_0]

thanks

[@UpsideDownFork]

You're welcome!

[@jeanh9641]

I did the same as you and it took at least 36 hours to get the house warm and comfortable. Next time I go away I am going to turn it down to 18 degrees Celsius. I will let you know how I get on.

[@UpsideDownFork]

Good plan!

[@_Dougaldog]

Holiday mode worked well for me, in this mode it consumed 10 Watts, and 'frost protection' kicked in a couple of times when first used last February as temperature dropped below 5C (Anti freeze valved would operate at 3C😧). I seem to remember house took about 24 hours or so for all to return to 'normal' (without any additional boosting), but those were very early days in the HP learning curve.

[@UpsideDownFork]

Good feedback!

[@canway88]

The Vaillant SensoComfort has absence mode, I just set that and have it come back on a day before we get back from holiday and no issues, DHW will be fully heated and house back up to temp... We do use Active mode though as this can boost / reduce the flow temp based on the room temp. Makes no difference to efficiency vs outdoor temp only (2 year experience with AroTherm Plus)

[@UpsideDownFork]

Thanks! I've noticed that the people who have efficiency issues with active are the ones who have their heat curve way off! Once the heat curve is correct then the difference between active and inactive is virtually nothing in normal day to day use but definitely useful for a situation you describe!

[@canway88]

@@UpsideDownFork yep - our heatcurve is bang on, easily tested by switching to Inactive... the advantage of Active is that if you have a situation like doors left open or heavy defrost cycles then the unit can boost the flow temp to get things back to the desired temp quicker... with out the room temp influence it'd take ages

[@bringiton8989]

People's experience of this is going to be very different as you say. I've done a full renovation of an 1860s property, so lots of internal wall insulation. I also put 25mm rockwool on the inside face of the cavity walls in the extension and air sealed the blockwork. I wanted to slow the bleed rate into the walls so the air temperature is more responsive. Of course, the UFH flooring is thermal mass, but it warms quickly as heat is directly applied. I'm pretty happy with it - I can recover about 0.5C/hr from 15C downstairs, but it tapers quickly and that final degree takes ages. The heat pump naturally maxes out due to the cold concrete creating a large dt, which helps at the start. The downside is that the upstairs radiators don't do much until the concrete is warm and the system rebalances - I didn't anticipate that and I hate getting out of bed when it's cold! I'm hoping for a more even experience when finally commission the mvhr. It's fun what you learn.

[@UpsideDownFork]

That's sounds fun! I love a good experiment! 😀

[@robynrox]

Nothing much to add, really, except that I think there ought to be an intelligent system that just works it all out for you, and also it might be worth using a setback temperature just to keep mould growth from happening. On a personal note, I've completed my planning application so hopefully they'll decide that in my favour over the coming months and I'll get my HP some time in the coming Spring!

[@UpsideDownFork]

There are some smart tools but us control freaks like to get involved unnecessarily!

[@darrenadams2640]

​@@UpsideDownForkI have said before that as this has so many variables it would be a good use of AI. But then again, us control freaks will still want to over ride it 😂

[@andrewcoles4271]

@@darrenadams2640 I'm developing an AI heating controller, and can confirm half the fun is learning from it how to be a better control freak 😆.

[@QuattroUK2011]

I am the 1% :) I'm going away for a week during the new year and have been thinking about this topic a lot in my head. I think I am going to set our heating to 16C whilst we are away, the night before we return I'll set it to 21C overnight during the cheap time and then get it to run at it's normal 20C during the day (we return in the evening).

[@UpsideDownFork]

Thanks for being part of the 1%! Sounds like a good plan.

[@Jaw0lf]

I do believe that maintaining the thermal mass is a huge factor with an ASHP as it heats the home much slower. Dropping back a few degress is no doubt the best way, but I would not turn mine off.

[@UpsideDownFork]

Wise decision!

[@crm114.]

Depends upon what time of year you go on holiday and how long for. If in the Winter, I would set a set-back temperature. Most heat pumps have a holiday mode which turns the hot water off and the temperature to the set-back value.

[@UpsideDownFork]

Agree!

[@Lawrence7of9]

Turning off hot water is obvious. Also, time of year, I turned off entire ASHP during Summer breaks and remote engaged it a few days before returning. This time of year definitely not let house get too cold, but set back as you suggested.

[@UpsideDownFork]

Agree!

[@M0j0]

Perfect timing. I'm off on Holiday tomorrow. Good experiment to try would be to take a manageable piece of furniture outside and see how long it takes to cool to external ambient temperature using the thermal camera. Would help towards understanding thermal mass perhaps 👍

[@UpsideDownFork]

Oooo, I like that idea!

[@bobphillips2188]

Interesting that everyone's an expert now ha ha! I use the holiday settings feature if I'm away for more than a few days, the house is always toasty when set to come on 24 hours before best estimate of my return (I might decide on a quick side trip on the way home - I'm usually driving, in my 17 year old diesel Volvo, 800-1,000 'range'... - but I'm not crying over an extra day's kWhs), it's as if I was never away. I wouldn't bother with any of that if it's only a weekend trip, just leave it on. I don't use an app, life is too short, and when I'm away the last thing on my mind is the heating! I DID drive myself nuts during the first year or so I had the pump looking into the 'best settings', but these are pretty much down to the individual situation, which model of heat pump, and personal preferences. I have an 11 kW Arotherm (pre-Plus) unit, free on a 100% grant, and it gets a touch colder in NW Scotland than in the soft south, and for longer each autumn-spring too, so my unit is never switched off, I just let the weather/temp sensor do its thing, even in summer (pretty cool here, there was some heat pump action every day, but only pence-worth). Compared to the cost of solid fuel central heating, the heat pump is hugely cheaper, maybe 35% of what heating and hot water used to cost me, although a lot of that difference was compromised by the massive price rises for lecky just as the heat pump was being fitted... Even so, it costs me about half what I used to pay in actual money, ie, for wood and coal pre-price hikes and pump installation, and lecky at today's prices. I don't run an EV (no money for that anyway, and the far NW of Scotland is no place to run low on juice), and my night-time kWh consumption on setback must be almost zero. I love my heat pump, only a little paranoid about what it might cost to fix/replace any of it when it goes wrong, which it will at some point, even Vaillants are not indestructible. That's the problem with people like me - dirt poor, health issues, none of this my fault - being given heat pumps; who's going to help and pay if a big bill comes along? Sorry for the rambling on! But if you can afford foreign holidays and EVs and all that, you can afford not to obsess about the heating. Get it dialled in to about the best you can do, then get on with life and let the heat pump look after itself - did anyone with a pump ever get so nerdy over their gas CH...? So, I'm kinda with folks who DO get nerdy, because I am as well up to a point, but then live life, and definitely don't install another flipping app!

[@UpsideDownFork]

Good points! I make these videos so that people can learn from my experience and make informed decisions. I totally agree that life is too short for fussing about these things, but life is never too short to help others.

[@kenbone4535]

I like your videos and I'm a heat pump engineer.

[@UpsideDownFork]

Thanks Ken! Keep up the great work you do as a heat pump engineer and feel free to correct me when necessary!

[@darrenadams2640]

I hope you are one of the good ones and not just a plumber that has done a basic heat pump course and become a heat pump expert. 😁👍 Maybe you are Heat Geek Elite certified? 😉

[@UpsideDownFork]

@darrenadams2640 you can see Ken in action here images.app.goo.gl/bdepNLQ6RCu2TjmD8

[@justinjoanknecht3475]

Got a short weekend break coming up myself but think I will just leave untouched for this short break. I have used holiday mode on the DHW before for longer trips and that obviously worked a treat. I only got 300% efficiency (only!) in November so am considering tweaking my curve though, although uncertain how much of that is down to the time shifting a little 1c boost on the 2330-0530 IOG cheap rate (and it seems that approx 67% of my heat was generated in that slot). All in, 144kWh used for November, of which 97kWh was at 7p and the remaining 47kWh was at 26.72p. So under £20 for the month and that doesn't even include when the solar was powering it during the day and a free session from Octopus! Very happy. Let's see how December goes. At least my export tariff is up now from 1st Dec :)

[@UpsideDownFork]

We did have a cold snap and running overnight at cooler outside temps will impact the COP but as you say, worth it for the lower running costs!

[@Crazydiamond_1974]

Great result!

[@cinnamondonkey2397]

Some home insurance policies require the house to maintained at or above a minimum temperature - I was notified 15c by by own insurance.

[@UpsideDownFork]

An interesting point that I hadn't considered!

[@mauriceegan8476]

Thanks for a great video as always

[@UpsideDownFork]

@@mauriceegan8476 thanks for watching 👍

[@davidstewart1153]

I made some mistakes last winter doing this. My thermostat has a couple of remote sensors so I put one in the basement, the coldest spot and where most of the water pipes are. The thermostat control logic was thrown off by that sensor. The water heater (separate heat pump just for this) also has control logic like a car's traction control, where the Off switch isn't Off. I think I'll do better next trip in understanding how the systems work. It is nice to remotely tell the house to wake back up, I'm coming home.

[@UpsideDownFork]

Thanks for commenting! Great to learn by experience. I'm running pure weather comp so only the outside temp does anything in my case.

[@adus123]

I listen to you on my phone while I'm working my phone is in my pocket, before I thought about liking or commenting the video has ended and gone on to the next video, so in this scenario I don't normally like or or comment. That's the only reason

[@UpsideDownFork]

I've got to stop being so abrupt at the end! Thanks for the feedback.

[@SolAce-nw2hf]

I would just let it go to 15C and resume the schedule 24 hours before getting home. That should be plenty of time in most situations.

[@googletitsfost]

Took ours about 2-3 hours to go from 15 - 20c, it ramped up the flow temp to 50c until it got to 19c then dropped to 40c and finally 35c.

[@UpsideDownFork]

Thanks for commenting.

[@devjon123]

Interesting and educational video. I'm still on gas, but going through the research into having a heat pump fitted. Mid 50's mid terrace with no EPC so Octopus quoted quite a high figure which they said would probably change once I had an EPC survey done.

[@UpsideDownFork]

Thanks and good luck!

[@darrenadams2640]

I don't subscribe unless I really like a channel and repeatedly watch the videos. I am subscribed to your channel and regularly comment. I very rarely use like as I don't want to over feed the algorithm! 😂

[@UpsideDownFork]

Haha, that glutenous pig of an algorithm! Insatiable it is!

[@Umski]

I guess in a way the principle of any heating method is loosely the same - with HP you have the added bonus of considering efficiencies - since in theory the heat loss is meant to be matched by the HP and sized as such, to add additional heat you would need to run it harder or for longer if you don't keep topping it up - with it being mild I guess turning it off wouldn't be an issue but if the outside temps dipped to the design temperature, the HP would then struggle to add more than what is lost, unless hugely oversized. I guess this is why people get their pants in a twist with gas since even a typical gas boiler will knock out 15-20kW until the rads get up to temp - to do that with a HP would kill the efficiency or never get up to the desired temperature. I insist that my parents leave their gas boiler (without WC) at a set back room temp of around 10-15C and then get someone to bump it back up to 21C a few days before they get back (even then they complain it's cold) - it will take a bit of time for the insides to drop to that set back and then the boiler can maintain if it loses more heat. I think I would be inclined to do the same if and when I have a HP, not that we're away much over the heating season - set back to lower temp and reduce the WC curve to just maintain at the lowest flow temp for efficiency - then in advance of returning let it ramp up itself in the most efficient way by changing the WC back to normal along with the normal room temp a couple of days in advance....

[@UpsideDownFork]

Great points!

[@hicksonb]

id be interested to hear how long you should hold on to a heatpump. Ours is 8 years old now, which means it's likely at least 10 years old. I've little to no way to engage with it or interrogate it, but that alone isn;t a good reason to change. But I do find it annoying I can't optimise it. Thanks as always for another good vid

[@UpsideDownFork]

You're welcome. Some.are saying that heat pumps are good for 20-25 years. Time will tell!

[@darrenadams2640]

Remember that thermal mass is also slowly releasing heat when the heating stops and hence slowing down the heat drop. For example, when you set 5 deg during Agile 4-7pm and 15 deg overnight. Hence, you may have found that the house cooled slightly quicker in the first day you were back due to there being less thermal mass. But it may not have been that noticable. I guess that when the house has lost a lot of it's thermal mass, it then heats up much slower (or at least uses a lot more energy) as some of the energy is spent regaining that thermal mass. Hence why it's not worth turning the heating totally off if you are away for just a couple of days or so.

[@UpsideDownFork]

Yep, I learned this the hard way!

[@ianhamilton3113]

Thanks yet again.

[@UpsideDownFork]

You're welcome!

[@typxxilps]

well, that is an example with a limited impact considering the outside temperature of 11°C or 12°C which means 14.8 is already quite close even though 3°C more which can easily be caused by sunny day and solar thermal gain inside depening on the architecture. At the end we shut it down which means heating on but only for a short period of time in the morning to avoid too much humidity. Water heating is here mandatory due to the bacteria Legionella cause you need to heat it up once a month or some do it once a week OR use the water from the boiler fully that it is exchanged quite often.

[@UpsideDownFork]

Thanks for commenting.

[@rodden1953]

Last year when i went away and had gas i turned the heating off but the house was so cold when i got back it took weeks to get it warmed up , do this year with the air to air im going to leave is at 19 , its cheap enough now and im old and feel the cold ..

[@UpsideDownFork]

@@rodden1953 smart move 👍

[@paulkearsley9509]

Excellent

[@UpsideDownFork]

Thanks!

[@edwyncorteen1527]

In the Summer mine is simply turned off and switched back on the day before our return, in Winter the temperature is set down and put back up a couple of days before our return, we cannot alter our compensation flow temperature remotely. In winter our heating is simply on 24/7 with power supplied on Intelligent Go and two powerwall batteries. Agile is far too variable for us, on IO there is no messing about required.

[@UpsideDownFork]

Thanks!

[@deathyyyyy]

Hi, just curious, do you run a higher flow temp becuase you use Octopus agile? We run a -2 outside, 45 flow, 15 outside, 25 flow curve but find the house is quite cold and struggles to heat (its from 1852) and the heat pump is basically on 24 hours a day.

[@UpsideDownFork]

Yes, it's Octopus Agile that makes me play the game. Last year we did run the heat pump more low and slow. Presumably your design temp was 45 when -2 outside then? As long as your radiators were all sized with these design parameters in mind, you should not be experiencing a cold house. Do you have all of your radiator valves open? Presumably you haven't retrofitted underfloor heating.

[@AndyKennedy]

Interesting figures, our heat pump currently uses around 15-20kwh per day so that fact yours only saved 30kwh over a week is remarkable. DO you think ours is sucking too much?

[@UpsideDownFork]

It is significantly colder now than when I was on holiday but your consumption will depend on the heat loss of your property. My heat loss is approx 6kW and my consumption this week has varied between 8-20kWh on different days due to external temperature fluctuations

[@elslopez]

When you consider the cost of the holiday, was 40KWh really worth worrying about?

[@UpsideDownFork]

Nope. Definitely not! It was mostly an experiment to be able to help and show others 👍

[@peterbruch8719]

We have 2 cats that stay at home whilst we're away, so I'll do what I normally do, which is turn the temp down from 20 to 18 in the peak periods during the day. With the battery charging at 7p/kWh, we probably won't save much.

[@UpsideDownFork]

@@peterbruch8719 thanks for commenting

[@poocharama]

At least you can play around with the weather comp in the Vaillant app. Mitsubishi’s MelCloud app is still in the dark ages.

[@UpsideDownFork]

I know I complain about it and take it for granted but having played around with Samsung, Daikin and most recently Mitsubishi, I appreciate the Vaillant even more.

[@davideyres955]

Interesting is setting the desired temperature higher running the heat pump over powered and increasing the temperature that the radiators run at? Or It is it running the same as a boiler where it’s just an on off tire situation.

[@UpsideDownFork]

Increasing the temp in the rads.

[@darrenadams2640]

​@@UpsideDownForkI also wondered why you did this. I guess it was to set a larger difference between outside temp and desired inside temp so the HP would set a higher flow temp to get their quicker?

[@HubbHubbs]

I dont have a HP, but I just turn heating down to 5 degreees when away for over a week, then just max power to get back to warm a few hours before coming home, I mean is there really much of a cost difference between peak and off peak and all that? If you've just spent a fair whack on a nice holiday, and saved a weeks worth of no heating, does the £5 vs £10 really matter. Or is it a much bigger gap than that..

[@UpsideDownFork]

@@HubbHubbs you're so right! If it wasn't for the channel and experimenting, it definitely would not be worth it!

[@KavanOBrien]

Don’t think anyone has discussed service of a heat pump , does it get done yearly and by the person who installed it ? Is the price dictated by the heat pump make or model , heard of this British company the other day looked into it and surprised nobody is talking about it in the heat pump world , the person that owns and runs the company is extremely intelligent and knowledgeable , having done a deeper dive into this company haven’t been so impressed in decades,

[@SolAce-nw2hf]

Service of a heat pump ? I think you can compare this of service of a fridge or a home ventilation system. There is very little to do unless it stops working or makes annoying sounds. There is something to be said for having someone come by every 5 years or so to inspect the unit, clean it inside and maybe have a look at the performance. But compared to a gas boiler these things are very low maintenance.

[@KavanOBrien]

@@SolAce-nw2hf oh ok , so really no cost on maintenance = didn’t know that , thanks .

[@SolAce-nw2hf]

@@KavanOBrien If you are worried something will break (which can happen), some kind of service contract could buy you piece of mind if it guarantees a response/fix time above what is required by law. I live in the Netherlands so I don't know what the situation is in the UK.

[@KavanOBrien]

@@SolAce-nw2hf I have a nephew that lives in Amsterdam, never been myself my sister said she like the people there because they say it as it is rather than not , I have always struggled with the concept of heat pumps, it makes sense in regards with ATA but makes no sense with ATW , for me at least to have a heat pump to heat the water to then heat the radiators for then to heat the house rather than just heat the house instantly with ATA ,maybe I’m crazy but personally I think ATW just seems daft, maybe be sanity is overrated.

[@SolAce-nw2hf]

@@KavanOBrien I have considered ATA heat pumps, but there are downsides. First and foremost ATA has a lot of noise inside, which is not there with radiators. Second, you need an inside unit in every room that needs to be heated. Third, these systems can be rather costly compared to a simple monoblock heat pump. Fourth, the comfort of radiant heat is far superior to hot air blowing through a room. My fifth reason is that it is simply ugly to have these inside units everywhere. It will simply not pass the WAF. But if you live alone, don't mind some noise and want instant heat because you are away a lot or have a home that is poorly insulated, an ATA unit may be better for you.

[@JonathanTracey]

do you have any feel for how long the thermal mass took to recover?

[@UpsideDownFork]

Fully recover? Probably 5 days. Mostly recovered in 3ish days but I have no objective quantifiable way of backing that up! I think I underestimated just how much thermal energy we put into our building and furniture.

[@3d1e00]

With regards to turning the heat off, are you saying you are moving the compressor to a state that it is normally not in? As in normally it will run at a minimum rpm and you are putting that to 0 instead? If so is a 0 rpm start a thing it is meant to do often?

[@UpsideDownFork]

Yes, completely shutting down the heating system is what I tried here. Not recommended but i'm always up for an experiment.

[@ecoterrorist1402]

@ 6:11 You claim to be on full weather compensation temperature with no room influence, yet your weekly planner suggests otherwise. mine set to 21 24/7, i have stats thou in the bedroom that are set to 18, up the weather compensation 0.40 to 0.45 temperature to a max flow of 35 UFH, noticed the weather comp thing for best results for me are outdoor temp of 5 - 10 = 0.40 outdoor temp of -2 - 5 = 0.45 i'm finding that the Vaillent system is good, but the software does not make complete sense.

[@UpsideDownFork]

Why does my weekly planner suggest otherwise? The desired internal temp feeds into the weather compensation algorithm to increase or decrease the flow temp accordingly. If I had room influence on then the heat pump would ramp up or down based on the actual room temperature which it does not. More reading available here: energy-stats.uk/vaillant-arotherm-weather-curve-information/ Agree that the Vaillant software has room for improvement but compared to the Samsung, Daikin and Mitsubishi heat pump interfaces that i've tried, I don't feel so hard done by! If you are happy with your heat curve at 0.40 - 0.45, you may want to experiment with active mode which can bridge the gap between the two based on internal reference. If you are at or close to the desired room temp because you're on the correct heat curve then the difference between active and inactive is little to nothing.

[@darrenadams2640]

Why did you leave the hot water on?

[@UpsideDownFork]

Because i'm stupid. Nah, mostly because I was also experimenting with how much heat it was actually losing. I can't normally monitor that because we use it so quickly. More info coming in a dedicated video.

[@reallyme3573]

I see, you have a Vaillant, they are somewhat quieter than the average heat-pump. For most other brands, the best thing you can do is turn it off permanently. Without the noise you will have a pleasant home, so you won't need to go on holiday.

[@UpsideDownFork]

Haha. But if Southern California is calling, you just have to answer!

[@darrenadams2640]

Very funny. Does that apply to boilers too as my boiler is much more noisy than my heat pump?

[@reallyme3573]

@@darrenadams2640 It depends, for how long does it run ? An average heat-pump runs 24/7.

[@craigwalton0]

I will leave it on

[@UpsideDownFork]

Can't go wrong with that.

[@peterbee8892]

I'm in the 1 percent

[@UpsideDownFork]

Thanks!