Skip to main content

Updated on 12/12/23 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? 

@juliamc I've heard of Passivhaus, my dream would be to build a house from the ground up to those standards. But I think the lottery must lose a ball or 2 everytime we do it 🤣🤣🤣.

I'd happily build a house into the side of a hill for warmth, but hubby thinks I weird for that 😂. I love watching Grand Designs, can you tell? 


So nice to see such a lively ASHP discussion happening here!

 

Hoping this has provided some helpful thinking points for you, @Gum168 and others who might be considering a heat pump purchase soon!

 

As for the Passivhaus dream, I wonder if @TerryE might have any more advice on making that dream a reality?


We’re really excited to announce our Air-Source Heat Pump LIVE ‘Share your Experience’ online event on Wednesday 2nd March.

 

Want to hear directly from those who’ve already made the change to this low-carbon way of heating? RSVP to the event  and pre-submit your questions:

 

 

Look forward to seeing you there. :slight_smile:


My experiences of a hybrid heat pump/ boiler system

Under two years ago I took up an offer for EDF pay for The £8000 installation of a hybrid heat pump system.

I just had to pay £100 and EDF now claim back the RHI from the government for the next 7 years after which the system reverts to my ownership.

Initially the heat pump's circulation pump wasn't installed correctly by a company called Passiv.

However, issue has now been resolved by Passiv and overall I am rather happy with the solution where the heat pump is on my estimate about 22 hours a day and the boiler only 2 hours at most.

Currently I am paying 5p per kilowatt for 4 hours a night and 16 pence per kilowatt for 20 hours and I also have a Tesla 13 kW power wall battery to spread low cost electricity to about midday.

I am monitoring the cost of both the heat pump usage and the overall electricity consumption of the house and the heat pump is costing approximately £2.90 a day to heat the main six rooms in the house 24/7 and more rooms at weekends with an additional £2 per day for all other electricity costs.

I live in a large six bedroom, five main living room detached house and I'm using netatmo radiator valves to control when individual rooms are heated and to what temperature.

One surprising benefit is that now that I have removed The thermostatic radiator valves from the two rooms which have wireless thermostat connected to the hybrid heat pump system, leaving the four main rooms heating to 19° from 10:00 p.m. to 7:00 a.m. and heated to 21° from 7:00 a.m. to 10:00 p.m. makes the house nice and comfortable all the time.

This is a far more enjoyable home environment In that I am having the main rooms heated to a near constant temperature 24/7 rather than wake up to a cold bedroom in the morning and then go down into a cold kitchen and cold living rooms and wait for the boiler to heat up the rooms over the next hour or two.

There is a slight water flow noise from the radiators obviously 24/7 but apart from that all seems very positive and I recommend others consider this option rather than except the fear uncertainty and doubt around post fossil fuel heating in the UK.

However, when my fixed rate deal ends in may, obviously I will have to pay higher electricity rates.

What I really want next however is to connect at least one of my electric cars, the Nissan Leaf is the obvious choice, to a vehicle to home bi-directional link to allow me to use The leafs 30 kW low overnight cost energy storage each day.

However, as I have mentioned before, as far as I can see, there is no vehicle to home or vehicle to grid hardware available in the UK at the moment and apparently no prospect of there ever being so!

It seems to me that the electricity suppliers such as OVO, octopus and alike are just promoting vehicle to grid trials for the past 4 years as PR exercise and not really have any intention to roll them out for general public use :-(

What are other people's impressions of current situation and the future?

 


@Stephenjp I think the challenge at the moment is that the time of use tariffs aren't reflective of what it is actually costing suppliers, both agile type tariffs and the EV tariffs. 

Octopus for example have said their tariffs are currently a "loss leader to encourage adoption" 

Without a heavy subsidy these tariffs currently wouldn't exist given the current turmoil and pricing mechanisms. 

I am sure this won't always be the case but the transition isn't going to be smooth. 

 


We have a heat pump installed but Ovo still charge us the gas standing charge even though we paid them to remove our gas meter and cap the pipes, no one we have spoken to seem to understand that we no longer use gas only electric. It's a real disincentive to having a heat pump, we are trying to be green and do the right thing so this has really upset us as bills are so high as it is. Has anyone experienced similar?


We had our gas meter removed, by OVO, in April and it's been a pita getting our bills sorted out. I had several conversations with customer service and I'm not yet convinced it's correct. The bills on the app still show us paying the gas standing charge while the ones they email to us don't.

 

I would contact customer service (I use the online chat as it seems more effective) and keep on at them until they fix it.

 

 


@katiebelcher_ We had the gas meter removed last year by Octopus. It took a few days after removal for the meter to be taken off the national metering system, but the gas bill was amended to remove the standing charge from the day the meter was removed.

Is you gas meter number still showing in your OVO account?


We have no hot water at any tap unless it is run at full blast for at least a minute ,this has always been an issue since the ecodan  heat pump was installed , any ideas why 


Hi @Chip370 

I'm going to send the bat signal out to @James_N and @timtoos in the first instance as I think they have an Ecodan from memory.

I assume the water is heated via a hot water cylinder rather than any other means? When was the heat pump installed? Did you change the cylinder when the new system was put in? I assume you didn't have issues ith your previous heating system?

 

 


HI yes the water is heated in a hot water cylinder, no problem with the old system,  2 years now.

 


Hi @Chip370 

I'm going to send the bat signal out to @James_N and @timtoos in the first instance as I think they have an Ecodan from memory.

I assume the water is heated via a hot water cylinder rather than any other means? When was the heat pump installed? Did you change the cylinder when the new system was put in? I assume you didn't have issues ith your previous heating system?

 

 

Hi,

Our system was a new installation in a new house so there was no previous system to remove. 

Yes, the ASHP heats the hot water in a cylinder.

Are you thinking of changing an existing system to use ASHP/GSHP?

Hope this helps.

Thanks


HI yes the water is heated in a hot water cylinder, no problem with the old system,  2 years now.

 

1. Was it a new cylinder when the ashp was installed ? 

2.Any new pipes from the cylinder to the taps?

3 Is the cylinder in the same place as the old cylinder

4. Is there any difference with the tap closest to the cylinder?

5. Did you notice any difference in the pressure of the hot water when the new cylinder was put in?

6. Are the pipes insulated between the boiler and the taps?

7. What temperature is your hot water set to?

8. Do you know the make and model of the cylinder? 


The government and many energy-aware bodies recommend a move to Heat Pump technology, especially in new-builds. It is generally accepted that the most efficient of these is the Ground Source Heat Pump. 
I have taken the recommended step and installed a GSHP in my new build. This was 12 years ago and I do not regret the decision. My GSHP ideally benefits from  3 periods of “reduced rate”  electricity supply, and this I obtained from the Economy 10 Tariff.

HOWEVER
Economy 10 availability seems to be reducing - with nothing replacing it to support the increasing demand from heat pump users. This is compounded by lack of Smart Meter availability for these users.

Does OVO have words of encouragement for those of us who seem to be doing the “right thing” but finding fewer suppliers able to supply our energy supply needs..

Hoping for some encouragement….


I


After much deliberation, I finally decided to get a heat pump installed for my hot water needs. The other alternative was a gas geyser, however i decided i did not want to be reliant on gas for hot water. Having a 5.4kw unit put in. I want to gauge its performance with winter on its way, and if it is inline with expectation, i plan on moving it onto essential loads. My pv system should have enough power to run it during the day. After discussing with the supplier, the representative suggested that the smaller 3.6kw unit would be a better fit for my current reality and expectation, i opted for the bigger size though for the incase factor.. ie.. in case i decide i want a second geyser hooker up..  or in case in the future i upscale from 150l to 200l etc.. That and given the math.. power wise it should use about the same power regardless. It should have a nominal power draw of some 1300w, so hopefully i see a material difference in electricity useage. Will post some results in 2 months odd time when the useage cycles cycle through


Hey @Old Timer,

 

Welcome to the OVO Online Community.

 

That’s amazing to hear you’ve had a heat pump installed.

 

Unfortunately, OVO currently only offer Economy 7 Tariffs. If you moved over with a smart meter as Economy 10, it would be automatically changed to Economy 7 times. The truth is the manufacturing of Economy 10 meters is becoming rarer. Hopefully the energy market comes up with similar schemes or incentives in future. I agree it’s beneficial for the planet to financially reward customers who are investing in green tech. 

 

Have you heard of OVO Power Move? OVO are rewarding customers for shifting their energy use to greener parts of the day! 

 

We have lots of interesting discussions on the Forum about heat pumps and your knowledge could really help other customers:

 

 

 

We also have similar threads relating to the issue you’ve raised:

 

 

Hope this helps. 


@vokar you’ve taken the heat-pump plunge, and you’ve joined an illustrious group of OVO Forum heat pump early adopters. 

 

Any questions around the installations, the settings, the efficiency, I’m sure there’s someone here who can offer some advice. Keep us updated! 


HI yes the water is heated in a hot water cylinder, no problem with the old system,  2 years now.

 

1. Was it a new cylinder when the ashp was installed ?  YES

2.Any new pipes from the cylinder to the taps?  NO

3 Is the cylinder in the same place as the old cylinder YES 

4. Is there any difference with the tap closest to the cylinder? NO   ALL NEED TO RUN AT FULL BLAST TO GET THE HOT WATER , lived here 50 years and had never been a problem 

5. Did you notice any difference in the pressure of the hot water when the new cylinder was put in? YES VERY FAST NOW

6. Are the pipes insulated between the boiler and the taps? NOT SURE 

7. What temperature is your hot water set to? 50 

8. Do you know the make and model of the cylinder?  

The general feeling is to get a return valve to the kitchen tap. Or turn the stop valve down so water doesn’t enter the house so fast

if I turn on the tap before the kitchen sink then the water heats faster , same if I turn the shower on before bathroom sink heats faster 

this is such a waste of water

thank you


Is it to do with heat loss?  The old system heated your hot water to a much higher temp, so it needed less throughput to heat the pipes as it came through to your taps? Now you’re at 50 deg it needs more flow to heat up the pipe work and still be hot when it gets to the tap ? You could try lagging the pipes.


There is no problem With the actually heat at the tap I just have to have it on at full

blast to get the hot water there and as it flows so fast it splashes everywhere 


Ah - then turning down at the stop valve is probably the answer. That’s what our installers did.


Hi guys. 
I have a super insulated log house of about 110m2. It has underfloor heating, heated from a thermal store utilising an ASHP currently 7kw. I have 3.9kw of solar panels installed and look to store electricity in a battery.

Thinking of combining the thermal store and battery storage into one or maybe two, heat battery instead of the solar battery?

How do I size the heat battery necessary to supply sufficient heat to the floor?


I've had heat batteries (Sunamp) with a heat pump and I would suggest not to bother. Sunamp's technology for low temperature heat batteries that work with a heat pump isn't good enough yet. I don't know what other companies are doing so there might be someone else who has got their batteries working at low temperatures.

 

Storing electricity is a much better option than storing heat. You have more flexibility and the storage is smaller. My 6.5kWh solar battery is about 1/4 of the size of the 9kWh heat batteries we used to have. I can use the stored electricity to run our heat pump, charge the car, boil a kettle and loads of other things. All you can do with stored heat is heat water and the house.


Heat pump chimneys - never knew that was a thing...


Disadvantages:

Cost. They're expensive, even with govt subsidies. There's an argument that the subsidies actually increase costs but that's probably a debate for a different thread.

Here in Australia, a homeowner can get a heat pump hot water system for $33 with state government rebate.

 


Reply