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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

Jeffus
Rank 20
Rank 20
January 13, 2022

At this time it is more expensive running a heat pump than the combined gas an electric a year ago. This maybe due to the complete lack of control we have being part of the Heat Pump trial and the system being controlled by someone else. If we were able to heat the batteries using cheap off peak electric or solar PV this might inverse the cost. The sunamp batteries seem to be inefficient for hot water, always relying on an immersion to get the hot water to a useable temp. We also have a major situation with where the heat pump was installed as it now blasts our outdoor deck area with ice cold air, it was not ‘allowed’ to be more than 10 meters from the house. 

 

Did you use to heat your domestic hot water with solar PV and/or off peak electricity prior to the heat pump trial? 

Jeffus
Rank 20
Rank 20
January 13, 2022

The comment from @hambrook demonstrates how important it is to get the specification and installation right. We have almost identical systems as we're both part of the same trial. Mine heats the house very well, is located down the side of the house and, despite some of the water being heated with an immersion heater, is  costing about the same to run as our old gas system.

 

 

It is also complicated by the fact that we don't know if your pre trial setup was more or less efficient than that of @hambrook

Your pre trial setups may not have been identical, so the delta in costs may be different between old and trial setup. 

Putting aside the issue with the position of the pump. 

Newcomer
January 13, 2022

The comment from @hambrook demonstrates how important it is to get the specification and installation right. We have almost identical systems as we're both part of the same trial. Mine heats the house very well, is located down the side of the house and, despite some of the water being heated with an immersion heater, is  costing about the same to run as our old gas system.

 

 

Great comment. I think the EPC is a blunt tool to base a Heat Pump install by. Our home had a B rated EPC.  It does not provide room by room insulation recommendations. The company that did the install asked me for all the room sizes and I can not see how the doors, windows were correctly captured to produce the BTU numbers. The one Climavent Radiator in our kitchen dinner can not heat that room even if it was on 24 hours a day, so where did the BTU calcs / survey fail?

For our house we have rooms with 2, 3 or 4 external walls and whilst this house has cavity wall insulation, A-rated windows, loft insulation, the Heat Pump can not produce the heat to off-set the losses. I would love to to know how to externally clad and render this house? Are there grants to do this work? I think some ‘follow up / snag list’ would be good as well/ For instance we had to replace a single panel existing radiant in a downstairs loo as it never got warm after the heat pump install. Towel rails also only get Luke warm rather than hot 

Ecodan 14kw Heat Pump with 300L Joules Cylinder - 9 kWp Solar PV - 2x Tesla PowerWall 2 with Backup Gateway 2 - Tesla Model S 75D - MyEnergi Zappi & Eddi - Mixergy 250L
Jeffus
Rank 20
Rank 20
January 13, 2022

Great comment. I think the EPC is a blunt tool to base a Heat Pump install by. Our home had a B rated EPC.  It does not provide room by room insulation recommendations. The company that did the install asked me for all the room sizes and I can not see how the doors, windows were correctly captured to produce the BTU numbers. The one Climavent Radiator in our kitchen dinner can not heat that room even if it was on 24 hours a day, so where did the BTU calcs / survey fail?

For our house we have rooms with 2, 3 or 4 external walls and whilst this house has cavity wall insulation, A-rated windows, loft insulation, the Heat Pump can not produce the heat to off-set the losses. I would love to to know how to externally clad and render this house? Are there grants to do this work? I think some ‘follow up / snag list’ would be good as well/ For instance we had to replace a single panel existing radiant in a downstairs loo as it never got warm after the heat pump install. Towel rails also only get Luke warm rather than hot 

 

That is a shame. 

In theory an MCS accredited installer should have done a proper room by room assessment themselves.

They shouldn't be  making any reference to the EPC. The EPC is irrelevant. The only reason the EPC is needed is for the RHI payments. It has nothing to do with the heat pump related calculations.

I would hope there is some sort of on site  independent audit of installations as part of the trial to capture lessons learned? 

Newcomer
January 13, 2022

 

I would hope there is some sort of on site  independent audit of installations as part of the trial to capture lessons learned? 

I would LOVE their to be an audit of my installation by BEIS or Mitsubishi 

Ecodan 14kw Heat Pump with 300L Joules Cylinder - 9 kWp Solar PV - 2x Tesla PowerWall 2 with Backup Gateway 2 - Tesla Model S 75D - MyEnergi Zappi & Eddi - Mixergy 250L
Newcomer
January 13, 2022

Did you use to heat your domestic hot water with solar PV and/or off peak electricity prior to the heat pump trial? 

 

Yes every day. We heated the Mixergy Cylinder using 2 x 3kw immersions in the 4 hour Octopus Go period paying 5p per kWh. There is some debated on this, but I believe that is the most efficient way to heat hot water rather than a heat pump and a heat exchanger. Keep in mind my Mixergy pre-dates the newer ‘heat pump’ ready Mixergy cylinders. In the summer we would only partially heat the Mixergy this way using the Eddi to divert excess solar PV, once the Tesla Powerwall was full. You can set priority on the Eddi. I had it set to : 1) Charge Powerwall battery first, 2) heat Mixergy hot water 3) dump anything else into Tesla EV via zappi. In the heigh tof summer our Solar pV produces 50 kWh 

 

Ecodan 14kw Heat Pump with 300L Joules Cylinder - 9 kWp Solar PV - 2x Tesla PowerWall 2 with Backup Gateway 2 - Tesla Model S 75D - MyEnergi Zappi & Eddi - Mixergy 250L
Jeffus
Rank 20
Rank 20
January 13, 2022

This should be happening next according to the Energy Catapult website. They are the lead contractor

https://es.catapult.org.uk/news/electrification-of-heat-trial-finds-heat-pumps-suitable-for-all-housing-types/

"The EoH project now moves on to the monitoring and optimisation phase where the Delivery Contractors collect detailed performance data on the installed Heat Pumps and look to ensure they are performing within the expected parameters." 

Their contact details

https://es.catapult.org.uk/contact/

Newcomer
January 13, 2022

I would LOVE their to be an audit of my installation by BEIS or Mitsubishi 

This should be happening next according to the Energy Catapult website. They are the lead contractor

https://es.catapult.org.uk/news/electrification-of-heat-trial-finds-heat-pumps-suitable-for-all-housing-types/

"The EoH project now moves on to the monitoring and optimisation phase where the Delivery Contractors collect detailed performance data on the installed Heat Pumps and look to ensure they are performing within the expected parameters." 

Their contact details

https://es.catapult.org.uk/contact/

 

I think there are different Heat Pump trials underway with OVO. Never heard of Energy Catapult 

Ecodan 14kw Heat Pump with 300L Joules Cylinder - 9 kWp Solar PV - 2x Tesla PowerWall 2 with Backup Gateway 2 - Tesla Model S 75D - MyEnergi Zappi & Eddi - Mixergy 250L
Jeffus
Rank 20
Rank 20
January 13, 2022

I think there are different Heat Pump trials underway with OVO. Never heard of Energy Catapult 

 

Ovo is one of Catapult delivery contractors. Good point you would need to check, i haven't heard of any other heat pump trials with ovo other than this one which i have posted about before. What are the other ones you have heard about? 

Delivery contractors

Three locations and three delivery contractors were announced for the installation of heat pumps:

  • South East of Scotland – lead delivery contractor Warmworks working with Energy Savings Trust and Changeworks.
  • Newcastle – lead delivery contractor E.ON working with Newcastle City Council and Your Homes Newcastle.
  • South East of England – lead delivery contractor Ovo Energy working with Kaluza, RetrofitWorks, Parity Projects and SunAmp
M.isterW
Rank 6
Rank 6
January 13, 2022

The trial @hambrook and I are on is using heat batteries to allow electricity demand to be time shifted. There's been no information about what the trial is investigating although I'd guess it's some sort of feasibility exercise. Can a system be built that can be controlled by Kaluza to shift electricity use to lower demand periods? How well does the system work and how much electricity use can be shifted?

1992 4 bed detached house. Solar PV + battery, Zappi EV charger, Mitsubishi Ecodan ASHP and i-life2 fan assisted radiators.... No gas 😊