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Abby_OVO
Community Manager
Community Manager
January 10, 2022
SHARE YOUR EXPERIENCE

Heat pumps - What’s your experience of the benefits and downsides to an ASHP?

  • January 10, 2022
  • 106 replies
  • 5002 views
Heat pumps - What’s your experience of the benefits and downsides to an ASHP?

Updated on 03/07/26 by Abby_OVO

 

Advantages and Disadvantages of Air-Source Heat Pumps (ASHPs) - Share your experience

 

As one of the leading options in our journey to decarbonising the way we heat our homes, Air Source Heat Pumps (ASHPs) are really heating up (pun intended) and generating much discussion, both amongst the AHSP trialists here on the OVO community and in this recent article written by our content team covering both the advantages and disadvantages of this low carbon heating set-up.

 

We know a lot of you here have gained first-hand experience of life with an ASHP in 2021 and we want to give you another chance to share your stories and help others considering an ASHP installation in 2022 and beyond!

 

 As the article outlines one of the main benefits of opting for this heating system over alternatives will be it’s green credentials:

 

“They don’t give off any nasty carbon emissions”

 

How important was this as a factor in making you decide on an Air-Source Heat Pump and how do you think the positive environmental impact could be supported?  

@nealmurphy@M.isterW  - be honest here: did reducing your home’s carbon footprint play a factor in your choice to go for a heat pump? 

 

We know, as with any new technology, there might be some misconceptions about ASHPs which could be putting off other potential adopters. Have you heard the one about how noisy heat pumps are?:

 

“They can make noise – but not as much as you might think”

 

We’ve ‘heard’ that the noise of an ASHP hasn’t been the issue you might have been led to believe before getting one installed - isn’t that right, @James_N and  @jason.lewis? Can you dispell this myth once and for all?!

Was this a concern you had before the installation and if so what put your mind at ease when giving the go ahead to the install?

What would you say to others who might be concerned by the noise factor? Are there times that the pump might be louder than others or is it a constant hum? 

 

Cost is always a major factor when making home improvements and could be the deciding factor for some. As the guide calls out, currently installation costs for ASHPs are much higher than for a standard gas boiler replacement:

 

“They’re more expensive to install than a boiler”

 

Whilst I know many of you here are participating in a trial so didn’t incur these installation costs, there may be other financial impacts to consider such as the ongoing running costs. This can be complicated to work out, but is essential information. @Gingernut49 and @hambrook - What advice would you give to someone trying to calculate the affordability of an ASHP over other options?

 

 

For those considering an ASHP in future there’s some positive news ahead:

 

“You can get some financial support for installing one”

 

We’ve also seen a few community members with ASHPs who aren’t part of any trials that OVO are involved in, and we want to hear from you on this one! @Heatherd@plodder@Sean T@Graham110011@Roy_and_Becky and @PNorman - Did you get any financial support towards your installation or running costs? Any top tips for someone thinking of applying for this now? 

 

 

“You’ll need proper insulation to get the best out of your heat pump”

 

This is another big and complex factor to consider when changing from a gas boiler to an ASHP. Pipe insulation is one thing, loft insulation is another and the overall heat retention properties of a house can impact the cost effectiveness. @hydrosam and @Transparent @hambrook - How can someone work out whether their house is suitable for an ASHP or what changes might be needed first? Better to get an expert in, or reaching for the thermal sensors?

 

@juliamc  we know you have first hand experience of some DIY insulation post-install: looking back, any tips you can share on how to go about this, or would you now advise the installer takes a lead? 

 

And what about radiator sizes? -  @sylm_2000  we know you had changes made: Share your overall lessons for someone unclear on whether their radiators are fit for purpose in an ASHP home of the future!

 

 

Potential heat pump owners, over to you!

 

As it’s usually the largest contributing factor in the carbon impact of a household, making such a radical change to the way we do things (over 85% of UK homes are currently heated by gas) will no doubt generate plenty of questions. We’re hopeful that by having honest and constructive communities (like this one!) on hand to de-mystify the process, this will give others the confidence to take the leap -  @Jeffus and @Gum168, we know you’re both eco-minded but yet to invest in an ASHP- Has participating in discussions here altered your view of heat pumps or encouraged you to learn more?

 

What would be the number one thing you’d want to know before making the ASHP journey? 

106 replies

Peter E
Super User
Super User
January 3, 2025

@Countrylad it's good to get your experience with a heat pump on here for other people to see.

 

The issues that concerned me were:

The intial cost. Not just the capital but the cost of replacement parts and the cost to insure it against faults. It's worth carefully researching those.

 

Longevity. My old gas boiler lasted 24 years with only one replacement part. In the end it was the heat exchanger that was failing so it was game over but everything else was fine because it was in an indoor environment. A significant part of an ASHP sits outside in all weathers. I think the jury is still out on how that will last and what that will look like in 25 years time. Screening the unit can cause a microclimate issue.

 

There is a risk of damage to the outside unit if you have a simultaneous fail of the mains power during sub zero temperatures. Some designs have antifreeze valves that drain the water in an emergency should that occur but not on the system I was offered. They wouldn't add glycol antifreeze either to the outside water circuit as they said it increases the viscosity of the water and reduces the COP.

 

I had a disagreement with the installers about the size of the unit required and they specified a 7.5kW unit against my detailed GCH records of only needing 4kW peak at the specified lowest temperature. A 5kW unit was available but they wouldn't budge on that. A 7.5kW would have been constantly cycling, reducing the efficiency.

 

In the end I installed an A2AHP rated at 3kW for a small fraction of the price and it replaces about 85% of my gas use. I call it a discrete hybrid system and hybrid systems are common in the USA and worth considering. But, if you just want a direct replacement for the gas boiler then make sure you do your research.

 

Peter

Reducing my yearly fossil fuel usage with an EV (-900 litres petrol), A2AHP (-8,700 kWh gas) and Timed Immersion heater (-1,500 kWh gas)
BPLightlog
Super User
Super User
January 3, 2025

I agree that lots of information from anyone with experience is useful .. I’ve been following a whole host of both installed and about to be installed projects and most have been positive (albeit needing some questions and direction).
My own reflection so far is that with the gov grant, many installations are not that expensive at all. Couple that with an included insurance policy, warranty and offer on including any radiator upgrades in the standard price has made me progress towards a purchase and install. 
An oversized HP is definitely a negative but my survey has shown heat losses (we have a void underneath the wooden floorboard) which suggest the need for a 9kW unit. 
I'm still not committed to the install but most of my research is pointing towards the positives to go ahead. We will see what happens!

Bring me Sunshine ~ E&E {Solar PV, Battery Storage, Hybrid EV, ASHP and Home Assistant automation}
nealmurphy
Newcomer
Newcomer
January 3, 2025

Oversizing can be bad but, of course, so can under-sizing! I've got a 16kW high temp heat pump and I'm almost sure my house could have got away with a smaller model. If you play around with the heat curve you should be able to minimise cycling. Even with a large unit I'm still getting around 340% efficiency for heating.

Blastoise186
Super User
Super User
January 3, 2025

340% efficiency? Mind if I borrow some of that? XD

Securing energy by zapping security bugs... For that is The Blastoise Way! Remember, I'm just like you - AI Powered Evil Geniuses aren't Staff!
Newcomer
January 8, 2025

340% would be good. Going by the system info it varied daily from 2.2 to 3.7 from late November to now. Do you have any idea how yours went over the same period ​@Blastoise186?

In terms of capital cost, after replacement and decommissioning cost for my oil system (23 years old) it cost 3500 which I’m happy to spread over 20 years and that included putting in an insulated underground hot water pipe.

Samsung 12kw EHS mono quiet heat pump installed November 2024
Blastoise186
Super User
Super User
January 8, 2025

My system has 0% efficiency as I unfortunately don’t have a heat pump. I run on an all-electric Communal Heating system which has underfloor heating in my flat hooked up to a central electric boiler that covers the entire building. That means the heating and hot water is also wired into the landlord electricity supply and meter rather than my own.

It’s great for me because I can turn my flat into a 24/7/365 sauna and not pay a penny for it. :D

Securing energy by zapping security bugs... For that is The Blastoise Way! Remember, I'm just like you - AI Powered Evil Geniuses aren't Staff!
Peter E
Super User
Super User
January 8, 2025

Alexa. <boing> Room temperature 25

Reducing my yearly fossil fuel usage with an EV (-900 litres petrol), A2AHP (-8,700 kWh gas) and Timed Immersion heater (-1,500 kWh gas)
Newcomer
January 8, 2025

Oops I tagged the wrong person so … 

340% would be good. I don’t really have a sense of what real-life figures I might get

Going by my system info mine varied on a daily summary from 220% to 370% from late November to now (SW Oxfordshire). This included water heating. Over the same period the average daily outdoor temperature was -0.8 to 12.5 

Do you know the range of  yours daily over the same period ​@nealmurphy ? I’m trying to figure out how much I need to poke the installer 😏

Samsung 12kw EHS mono quiet heat pump installed November 2024
nealmurphy
Newcomer
Newcomer
January 8, 2025

@Countrylad I've not looked at individual months as it's easiest to look at the usage since installation which was 3 years ago. I'll take a note of the numbers today and report back in a couple of days to give an idea how it's doing in current conditions. 

Did you get any guarantee of COP or a suggestion of what it may be from your installer?

Newcomer
January 9, 2025

@Countrylad I've not looked at individual months as it's easiest to look at the usage since installation which was 3 years ago. I'll take a note of the numbers today and report back in a couple of days to give an idea how it's doing in current conditions. 

Did you get any guarantee of COP or a suggestion of what it may be from your installer?

I'm not sure that it's a guarantee but the scop quoted is 4.4, my average is 2.9 from about 33 days recorded

Samsung 12kw EHS mono quiet heat pump installed November 2024