Talk to me about air source heat pumps

[RidingMyBike]

We've just had an offer accepted on a house that needs a lot of work, including replacing an old boiler. It's been a longterm aim to have solar panels but we're also looking at an air source heat pump and had favourable comments from friends who have installed one - although they weren't on mains gas so have saved a lot not having to buy heating oil.

Any thoughts? Pros, cons? Things to watch out for?

https://www.desmog.com/2023/07/20/revealed-media-blitz-against-heat-pumps-funded-by-gas-lobby-group/ Proof that I was right, the Telegraph printed false articles funded by gas companies owner.

My workplace had one retrofitted and we all wore thermals under our uniforms in the winter. It was bloody useless. The radiators barely got warm.

Then it was installed incorrectly!

This!

We retrofitted an ASHP in our 1960s house, it was excellent. We won't be doing so in our current house which is Edwardian, as it's not suitable.

That's really interesting. I had similar suspicions and you can see the effects on threads like these where people who don't even have a heat pump are happy to tell everyone how rubbish they are.

We have a house built in the 1930s and asked our plumber about this. He stated that they were really only suitable for new builds with all the enhanced insulation/double or triple glazing etc. Get advice independent from a supplier.

Or the building was unsuitable. In which case it should never have been installed in the first place.

The heat pump industry damaged its own reputation by installing loads of heat pumps in unsuitable properties.

Heat pumps are complex things and you need to consider many factors before you choose one over the alternative.

They can work well in certain situations and maybe not surprisingly in new houses which have been designed specifically for them.

But in some other cases they can be a very expensive mistake.

Since this thread started we've had ours installed in 1930s semi. Along with new double glazing, UFH and some extra insulation in bay windows.

And... we're really pleased with it! House lovely and warm at a consistent temperature all day (great for WFH). So far it's cheaper to run than the gas central heating in the house we were renting.

Glad we ignored the Telegraph readers!

So you're comparing the heating costs with a completely different house (?) and sounds like you may have spent at least 20K on house improvements to get what might be a reduced energy usage.

I can tell you that 20K buys a hell of a lot of gas.

Can we see some actual figures on how the economics stack up ?

What was the cost of the insulation/heat improvements above and the heat pump, and what was your typical energy cost on heating per year before and after ?

You can be happy with your solution/installation -fair enough, but the question is does it make economic sense ?

inherited one in a house was useless expensive and cold and noisy - the heat exchanger is noisy with fan making a noise coming on and off. you cannot beat gas.

if you are building from the beginning and are detached with plenty of land then it might be ok but otherwise no.

We rent a house with one and hate it. They are very expensive to run, especially if you are out all day and would otherwise just need a blast of heating morning and evening.

The trouble is, they aren't a turnkey solution - it has to be properly specced and fitted, and you need to learn how to use it efficiently, including what temperature the water should be, when it is heated, and how fast the water flows through your property. If it's not working for you or your house, it doesn't mean it doesn't work for everyone! 🙈
We love ours but it has taken time to tinker with it to make sure it works well for us, e.g. we put it on all night when the electricity is cheaper and actually found it was better to run it 24/7 in colder months because it doesn't have to work as hard to heat up a cold house. It's absolutely the opposite of 'blast of heating' twice a day - that's just not how ASHPs are designed to be. Our house is a stable temperature 24/7 which is much more efficient and I don't miss the intense heat of the early morning and early evening and then cold at other times - especially as DH and I both WFH.
@RidingMyBike - great to hear your installation has gone well.
@LINDAHOAD - yours may well be old if you can hear it - we can't hear ours from the house at all.

@RidingMyBike yey pleased it worked out.
Same here ours installed earlier this year - not had a full winter yet so jury's out but so far so happy. Hot water is certainly plentiful and the heating has been coming on slightly overnight when cold to ticks us all over.
We've also got an EV and solar plus battery so proper green geeks. We work from home almost all the time though - I can see if not being as efficient an option if you are out of the house a lot.

We did need our gas boiler replacing though. Given the money and also mild mess involved (replacement of radiators and some pipework) this is not going to be a realistic prospect for families unless a. they have some spare cash lying around b. their house is suitable and c. they are prepared to invest to lower their carbon footprint. As it stands gas boilers still make more financial, if not environmental, sense.
But there is no need for the conspiracy theorists. There is a reason that most of Scandinavia have had them for years. Hopefully in future the government will be able to properly subsidise them and even sooner than that ban gas boilers from being installed in new build houses.

There is also a serious shortage of knowledgeable engineers around to service and install. Quite a lot of cowboys. this is what needs addressing most urgently.

Totally agree @StillWantingADog - we have solar, planning on ufh for the whole ground floor, an ashp makes loads more sense with these, obviously in addition to insulation.

We've had ashp over 10 years with Ufh and lots of ins - planning on land based solar to add to it - only good with the right conditions though

We haven't had it for a full year yet so I can't compare annual kWh figures. We bought the house, renovated, then moved in so no previous usage figures but the average cost per month from last months of winter, spring and into summer is less than previous house (which was same no. of bedrooms but terraced, this is semi) and also house before that (smaller but detached) at the point when energy prices went up. The terraced house (a newish one built in last 15 years) was terrible for insulation and poor quality double glazing.

It depends on your lifestyle and you do need to understand how a heat pump works to get the best from it. We have at least one person and often several at home almost all the time so constant low heat works really well for us. We also benefit from a heat pump tariff where we heat the water at certain time of day at a lower rate, haven't been on the tariff and needed the heating on yet but we'll tweak those settings when the weather gets colder.

The house was a wreck when we bought it, so we would have had to install radiators and replace ancient gas boiler anyway, along with the windows, slipped tiles etc. I'm not sure how much an entirely new set of radiators etc and boiler would have been for a big house like this. But the heat pump and UFH cost £12k, of which we got £5k paid by govt grant, so £7k cost to us in total. The cost looks pretty similar to the figures on here but I don't know how up-to-date these are:
www.theheatinghub.co.uk/central-heating-systems-costs-central-heating-boilers-prices

Thank you for resurrecting this thread, OP. I am about to have my cold, damp, rented, Scottish, 5 bed Victorian detached farmhouse renovated with ASHP, solar panels and full insulation so I'm very interested in how it all works. We're benefiting from the ECO4 grant, and have landlords who are willing to do their bit (new windows throughout, replaced external door, new radiators) so the capital costs are irrelevant to us. We're being allowed to keep our living room coal fire, which I think will remain a godsend in winter, and I already have electric oil filled radiators for the upstairs bedrooms should we need to supplement in winter.

I read that ASHP should run 24/7, which makes sense in winter, but is it OK to switch off in spring/summer, and back on in Autumn?

Yes, we turn ours off completely in spring and autumn. If you don't need any heat at all it can be turned off -- it's the frequent switching on/off you can't do. No switching it off altogether when you go out for the day; just change the temperature.

We don't actively turn ours off, we just leave the thermostat at the same temperature and leave it to take care of itself.

@RidingMyBike we're in Yorkshire too and looking at air or ground source. Do you have any recommendations for a brand/installer?

If you switch it off how do you get hot water?

intrigued by this ours is designed to never be switched off as such, it’s on a thermostat and comes on very early mornings currently as quite cool, plus twice a day to heat the hot water

Well, the pump doesn't actively run constantly. Our thermostat is set to 18 degrees, so the pump only kicks in for heating purposes when the temperature dips below 18. At this time of year it only kicks in for hot water, obviously. I'm in a HA newbuild, and we have the luxury of the Blue Flame engineers on call for any niggles. Niggles have included insufficient hot water (because the time on the control panel in the airing cupboard reset itself, unbeknown to me 😳), and some of the other houses in the row suffered because the device monitoring the air temperature was installed inside the airing cupboards...where it's always very warm! 😆 (I unconsciously avoided this by having the airing cupboard door open in winter to dry clothes in there!) So yes, teething problems all round!

Other than that, it's great- keeps temperature at a constant, and not expensive to run (this is an all- electric 2 bed house, and my annual electricity bill is about £1200 atm)

"My" package includes solar panels and a hot water tank, so I guess that's how. As it's a farm, we also have outbuildings, so tonnes of roof facing different directions. I'm told we'll also have a battery for energy storage.

I honestly would be very surprised if you don’t need the heatpump at all between sprint and autumn to heat the water.

we also have solar and a hot water tank and there is only enough solar to fully heat the tank on a run of sunny days- happened in June but no chance last few weeks with it being so cloudy (round here anyway). Happy to be wrong about this.