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?

Our ASHP has a 25 year guarantee. The annual service charge is £70 which is less than our old oil boiler was.

Thank you everyone, this is really useful. It sounds like there less good for older/period properties which this one isn't, although it does need insulation doing. It's EPC is currently an E!

@MrsJamin yes, Mum is a Telegraph reader. That explains where she's getting all the ASHP stuff from despite knowing no one who has it?! Are they also the same about electric cars as she has similar views on those?!

@RidingMyBike yes they are anti any green alternatives! It's horrendous how biased they are and they are impacting the buying habits of a wealthy subsection of society to the detriment of the planet :(

I was not influenced by the Toryadorer about ASHP or any other green option. I was influenced (see above) by the professional study I had done which came out at £15000 for the ASHP installation plus £10000 for insulation. I'm 75 so I would never recover that cost in my lifetime, especially as electricity costs are rising and ASHPs need to be on all the time.

This is what we'll do @Grantanow - get a proper survey etc done with costs. But we are in a different position as this is a house we plan to live in for 15-20+ years, we're buying it in quite a state, and will need to do the insulation and the replacement boiler anyway.

The way an ashp works is completely different to a gas boiler in terms of how you manage heat. It needs to be on all the time because if you let any area drop too much in heat it costs even more electricity to heat it up again. It's on very low all the time, basically. So yes electricity is on, and you'll need more of it in the winter but you won't be needing any gas. If your house needs £10k of insulation I'm not sure why it wouldn't be needing to be done for any heat source, otherwise you're just losing heat?

I had ASHP installed in December. Am very happy with the warmness of the house. I like how the temperature of the radiators is lower so the house feels consistently warm rather than too hot then too cold.
Am using 1/3 of the energy I was the year before so happy with that too (realise it has been a milder winter!). I work from home so just have it turning itself on and off with thermostat between 5 am and 9pm, then off overnight.

They installed a new larger pressured hot water tank (so nicer showers!). No more icky cold water tank in loft. They replaced all my 90s radiators with double panel ones to increase surface area. They look smart too.

I was on oil before, no gas in our area. So no more installation and maintenance of big ugly oil tank and having to get oil deliveries. Also avoid the fluctuations in oil prices which are worse than for electricity (oil has doubled in the last month and still going up). Think ASHP doesn't yet make financial sense for someone with access to mains gas.

House is a very large Victorian property with brick walls, old double glazing, dubious loft insulation and 2 open fires. Installer was recommended by a Mumsnetter. They did lots of energy calculations obviously my house needs a larger heat pump unit than a modern insulated house with underfloor heating! I got the full RHI grant of 11K paid over 7 years (no longer available after april), so I will end up paying 5K.

Can't comment on longevity of system obviously.

Happy to answer any specific questions.

My mum has one in her new build and it’s very efficient but she hates it because it was installed at the rear of the house so she can’t eat outside without being blown with air and it sits under the bedroom window and is so noisy it keeps her up in the night. I’m not sure if she’s just not worked it out yet though.

Does the house have a cavity wall? Ours doesnt so I doubt air source heat pumps will ever be any good for us.

@PurBal

My mum has one in her new build and it’s very efficient but she hates it because it was installed at the rear of the house so she can’t eat outside without being blown with air and it sits under the bedroom window and is so noisy it keeps her up in the night. I’m not sure if she’s just not worked it out yet though.

It sounds as though that's been very badly designed. You can place an ASHP anywhere, although obviously it's easier to stick it on the house. Ours is on the back of the garage so we can't see or hear it from the house or garden.

Ours isn't very noisy though. Our NDN have a bedroom that overlooks our garage and have never complained about the noise (and believe me, they would!).

It does have cavity walls in the original part according to the EPC, but half the entries on that say 'assumed' so we're waiting for the building survey to come back! It's likely as that part was built in 1930s when they were doing cavity walls?

@PurBal hmm, I wonder if she's adjusted the settings? The person who posted above you doesn't have theirs on after 9pm so presumably not noisy at night?

Although I am wondering if ours could go at the front as there's a sort of strangely shaped side area where the wheelie bins are tucked away. It would be very unobtrusive there.

Yes @RidingMyBike if you've got enough space there I'd have thought that was a good idea. We are lucky with a detached house with a big space at the south side of the house which was perfect to site our ashp. It does blow out very cold air, though, so I wonder how that will feel in summer, as that's where I put all my pots to get the most sun. No biggie though, much more important to get the energy use sorted in the house.

A lot to think about! Still two weeks to go until we get the building survey so the whole house purchase is nowhere near definite yet!

Hmm, that does sound a good fit for the weirdly shaped side area. It isn't somewhere I'd have plants (we were also thinking about putting an EV charging point there), but otherwise it'd just be the wheelie bins. And it's away from the neighbours.

MrsJamin makes a fair point about the need for insulation and current heat loss. My house has secondary double glazing and good roof insulation but would need solid wall insulation to cope with an ASHP's cooler heat output. My point is that I can't recover the cost of the ASHP + insulation in my lifetime. A modern gas boiler comes at about £4K and even with higher gas prices I'm still ahead financially against a capital outlay of £25K plus continuous electricity costs.

i have had all types of heating. heat pump noisy and difficult to adjust to your needs every day. electric expensive but ok. gas is far the best
you cannot beat it - if you are not on main gas - lpr or oil - heat pumps hit and miss not warm enough. if yu have to have supplementary heating there is really no point.

Had ours 11 years underfloor heating well insulated barn conversion. Constant hot water works well no loss of wall space. Cost is dependant on how high you have each room stat.

My friend recently had ASHP installed, latest one from Mitsubishi.
He has an equivalent of an EPC A house, rads, and says the output of the ASHP is perfectly good.

I am no expert but I was talking to the lead engineer on some new building projects for our LA today.

He is appalled that the government has such an agenda for air source heat pumps. They may use less energy than other heating methods (although apparently not as much less as you may have been led to believe) but they run on electricity, which currently costs three times as much as gas.....

Broadly speaking here, but if you can get mains gas, I'd do that.

Why have you resurrected a thread a year later? I don't see the point.

I keep thinking about ASHP for ours but our insulation won’t be good enough. I sometimes wonder whether it will be the diesel car of the future - pushed by the government as greener but isn’t at all.

The ‘beauty’ of ASHP is the gov is going all out on green electricity. It’s not going fracking for oil or exploring for gas.
Oil and gas fluctuates in price, and current issues are caused by the war.
Whether or not we’ll see ‘cheap’ electric, or gas, again we don’t know.
Whether all the demands on electric will increase the price of electric we don’t know.
But if you have a suitable house, and your oil or gas boiler needs replacing, ASHP should be a consideration.
It would not surprise me if the government acted in some way against GCH or Oil in the future.