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Original poster

Air source heat pump

37 replies

Avocadoandlemons · 31/01/2022 13:38

What do I need to know about these!?

Might be getting a house with one

Pros / cons / things to watch out for before we buy?

Are they easy to upgrade in years to come as technology improves?

Thank you!

OP posts:
TheDeckchairGardener · 31/01/2022 13:59

We had one installed in September 2021 thanks to the Green Homes Grant. Our house is 1950s and previously had a direct electric boiler which only came on during the off-peak hours of electricity (we have economy 10 tariff) as it was so expensive to run. The advantage of the heat pump is we now have a consistent temperature at a slightly lower electricity cost although we keep our thermostat set to 19 degrees which is probably not high enough for most people. We are hoping to make further improvements by installing a smart thermostat/controller which will help our heat pump make the most of the off-peak electricity and get more efficient windows.

If you are buying a modern, well-insulated house, you probably don’t have anything to worry about, although with the cost of electricity about to rise, bills are still a concern.

We haven’t had ours long, but we were given a 10 year guarantee with ours, so I am hoping it will last a long time! It can be quite noisy when it is running (like an idling car) and it is recommended that it has an annual service.

There aren’t that many companies that specialise in this technology - out of 3 companies local to us - only 1 was willing to come and give us a quote although this was due to the green homes grant causing a huge flurry of interest. As gas boilers are set to be phased out, I think this may change in the future.

Original poster
Avocadoandlemons · 31/01/2022 18:06

Thank you

OP posts:
EmmaGrundyForPM · 31/01/2022 18:32

We had one fitted 4 years ago. Our house is 1960s but very well insulated. No downsides as far as we can see. The unit is guaranteed for 25 years, which is a lot longer than most boilers.

Original poster
Avocadoandlemons · 31/01/2022 19:32

Great to hear. Thanks

OP posts:
silversun · 31/01/2022 22:11

Make sure you check where the outside unit is situated, we had one installed last summer underneath our bedroom window and found it to be noisy enough to wake me up at night when it randomly fires up.
The idea is the system maintains a constant temperature so depending on how hot/cold it is outside it will turn itself on and off regularly to achieve this.

Darley368 · 31/01/2022 22:19

Make sure you get details of the actual running costs. I had a house with one once (a Mitsubishi which I had installed in a flurry of greenness) and was told the manufacturer said it was 1:4 efficient. Based on my experience and electricity bills that simply was not true. They are also least efficient in cold weather i.e exactly when you need them. Electricity is more expensive than gas and the hum they generate is quite penetrating.

I have not been tempted to have another one.

Original poster
Avocadoandlemons · 31/01/2022 22:23

Really good to know. Thank you. I'm a noise freak so that info is quite key!

OP posts:
Original poster
Avocadoandlemons · 31/01/2022 22:26

@silversun @silversun Would it wake you up if the window was closed?

Think the unit is outside bedroom but on a wall where there isn't a window. However I hate noise and light at night and can't exactly ask if we can stay overnight in the house before we put an offer in Grin

OP posts:
Hairyfriend · 31/01/2022 22:40

We are renovating a derelict property, the original part build in the 1930's. If I had £1 for the amount of passers by telling us to get an air or ground source pump, and what 'green energy' are we installing is actually rather astonishing and I would be rich by now! I have looked into ground and air source pumps in great detail. Also wind turbines and other 'eco' devices going forward.

My understanding is that unless you have a new built, with 50cm of insulation, a ground source heat pump is virtually useless. They work best in warmer weather, and you will need to supplement with gas or electric in cold weather Confused They are also noisy!

I looked into a smallish, garden wind turbine. The cost would take 25yrs to even break even from the cost of installing it!!!

crackofdoom · 31/01/2022 22:45

I have a heat pump in my new build HA house. It's underneath my bedroom window (at ground level- bedroom is on the 1st floor), and I honestly hardly notice the noise- and I'm pretty sensitive to noise, too.

Overall, I think it's brilliant, and my neighbours love theirs, too.But because it's a new build we have underfloor heating- such a luxury. I gather retrofitting underfloor heating is quite the challenge.

crackofdoom · 31/01/2022 22:47

Hairyfriend we certainly don't need to supplement our heating with anything in cold weather. My thermostat is set at 18, but my neighbour's is on 21, and it works fine for her too.

Hairyfriend · 31/01/2022 22:52

@crackofdoom- great to know yours works well, but you said its a new build you have? I thought retrofitting insulation in an older house, and trying to use an air heat pump was useless- unless the insulation was 50cm thick??? Might be wrong- just going by the advice given thus far.

Didicat · 31/01/2022 23:18

Our heating bills make me worry. We have a large house built in the 1960s the pump was fitted 8 years ago but the owners didn’t improve the insulation or the radiators or the windows…. To say it costs a small fortune to keep the house warm in comparison to gas. We don’t keep the house that warm 15c mostly and sitting room we have the wood burner on the whole time we are home - which is toasty.

Have been increasing the roof insulation, considering insulation exterior wall and saving up for better windows, before we do the cosmetics of the house.

For them to be efficient you need to change more than just your boiler.

Soontobe60 · 31/01/2022 23:33

From what I’ve read about them, which is a lot, they work best with a well insulated house that has underfloor heating fitted. That’s because you need a big surface area to heat up the room at a lower temperature than a radiator can heat up to, and radiators have too small a surface area. The room temperature is slowly raised and then kept at a steady temp - eg 20 degrees, as opposed to radiators that heat the room up quickly from cold to 24 degrees but quickly cool down again.
So, a draughty building, poor insulation, only radiators all will mean that a ground or air source heat pump could turn out to be an inefficient - and costly- piece of kit.

Original poster
Avocadoandlemons · 01/02/2022 00:01

Ok cool thanks. This has UFH downstairs . Upstairs traditional rads though.

Epc b

Double glazing.

OP posts:
fridascruffs · 01/02/2022 03:36

I had one put in a year ago cos my oil system failed ( no gas option.). I am using the RHI scheme to offset the cost of installation. My house is prewar council, but I had the old part of the house insulated with 10cm of insulation a few years back. There's a 1980s cavity wall extension that is now colder than the old part of the house so I'm thinking of we externally insulating that too, if I did that it would be fine. I had t ok have bigger radiators put in as part of the installation. I have also found that the we efficiency is not 1:4 as advertised, it's more like 1:2.5 so far. Cost wise it was about the same as oil when oil was about £600 for 1000l, but now that electric is going up a lot it will be more I suppose. But I didn't want to pay for a new oil system which would've been, say half the cost of installing the heat pump system (but iq wouldnt have for RHI so ultimately ASHP is cheaper), because oil is being phases out. I live in a rural village so options are limited. A neighbour had solar panels and a Tesla wall installed- massive upfront costs.

fridascruffs · 01/02/2022 03:37

Wouldn't have been ELIGIBLE for RHI that was meant to say.

Iknownothing · 01/02/2022 04:52

Following with interest - we’re in the process of getting quotes. My main concern is noise as we live in a cul-de-sac in a very quiet area. My neighbours are very into wildlife spotting in their gardens (opens onto woodland so very frequent visitors of all types). I’m concerned if we have a heat pump on the front of our house it would be too noisy and it’s not something we can put in and then change our minds easily if it’s too much.

unidentia · 01/02/2022 05:56

Like fridascruffs I had one installed in December after an oil system failed (in a village with no gas). Large Victorian property.

I'm thrilled as I have central heating again, installation only took 2 days. They replaced all the 25 year old radiators with shiny new ones and a nice big pressured hot water tank. I like that the radiators are hot but not too hot, so a constant heat. And no more having to fill the ugly oil tank! With the RHI I will end up paying only 5K.

Running costs hard to tell as this year has been very warm compared to the snow last year!! Cheaper than all electric, about the same as oil before it went up. (Dec/Jan both running at £150/month). I can't think it would make financial sense for someone with access to town gas unless an insulated new build.

unidentia · 01/02/2022 06:11

@Iknownothing - the noise, luckily I don't have close neighbours so didn't have to worry about that. I've got a big 14kW LG unit. There were decibel ratings provided so talk to your installer. If I'm standing in my utility the noise inside is about the same as my old boiler running inside. Outside louder. Also the noise is higher pitched than the boiler which sort of rumbled. There's a settings option to have it run quieter at night but I haven't used that. Also the radiator pumps are in the airing cupboard next to my bedroom so theres some noise from that too. Have got used to that now. I would definitely ask your installer to visit a previous client to hear it running.

EmmaGrundyForPM · 01/02/2022 07:21

@Hairyfriend our house is 53 years old, and the ASHP works fine. We do have CWI and double glazing, and we had a few of the radiators replaced. Our house is warm and the system.works well. I agree it wouldn't be suitable got a draughty older property but we retrofitted it to ours and its great.

Our neighbours were so impressed with seeing ours that they have had one installed (1980s house,) and they love it.

gogohm · 01/02/2022 07:37

I'm currently investigating but several of my neighbours now have them, houses are 15 years old so the boilers are starting to be temperamental! You need good insulation and potentially larger radiators from my research

SamMil · 01/02/2022 07:45

We've been in a house with ASHP for a year now and it's working well. We have underfloor heating downstairs and radiators upstairs. The house is triple glazed and well insulated so stays nice & warm.

The pump does make a humming noise when it is on, but I only hear it when I'm outside.

trunktoes · 01/02/2022 08:01

We have one for our pool. It uses a lot of electricity when it's cold outside

TheDeckchairGardener · 01/02/2022 09:48

To those saying you need tonnes of insulation and underfloor heating, that is not our experience. As I mentioned above my house is 1950s and not particularly well insulated. It has the standard cavity wall insulation and loft insulation and (very old/inefficient) double glazing and yet the heat pump is working well for us. I will mention though that we have a Samsung heat pump which heats the water to 55 degrees. Some of the older heat pumps only heat water to 35 degrees so will take much longer to heat a property. We had some of our radiators replaced with slimline double radiators to give a greater surface area (but without taking up more wall space).

Regarding the noise, I was a little disappointed at first as my last electric boiler made virtually no noise whatsoever but you quickly get used to it. It isn’t on constantly and I would say that the exterior oil boiler of a property behind me is much noisier!

Overall, I have no regrets although I wouldn’t have been able to justify the cost of installing one without the help of the grant!