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Air source heat pump (ASHP) retrofit, running costs and experience of buying and installation?

  • 2 September 2022
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Hi All, I’m wondering how the experiences have been for people who’ve installed a heat pump to an existing property.  

What was the buying experience like?

What was the install experience like?

How has the performance been?  And what about running costs of the ASHP vs whatever you had before?

Cheers in advance

Steve

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Best answer by nealmurphy 2 September 2022, 17:27

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Howdy @Stevea !

I’m afraid I can’t help you there myself, but I know a few people who can. Let me introduce you to @hydrosam @M.isterW  @juliamc @nealmurphy and @ArundaleP for now, as they might be happy to talk with you about this. :)

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Brilliant, thank you @Blastoise186 

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Hi @Stevea 

Having been awakened from my slumber by @Blastoise186 I can confirm that I am indeed happy to talk with you about this! :)

I’m not sure if you’ve already been through the various threads on the forum such as 

If you click on the heat pump tag of your post it should find some others.

For disclosure, I got my heat pump through the OVO Zero Carbon Heating Trial.

The price of the system was just under £15,000 which included supply and installation of a High Temperature Air Source Heat Pump, control unit, new water cylinder and 3 upsized radiators. My property is a 4-5 bed 1950’s detached bungalow with loft conversion. Good roof insulation but poor wall and window insulation.

Installation took around 4 days of which we were without heating / hot water for around 1 day. All went smoothly and couldn’t fault the installer, though some installers are better than others, so go with ones with a good reputation. www.heatgeak.com is a good place to start for advice.

I’ve had the system since Summer 2021. Energy costs over last winter were slightly cheaper than the previous winter when I had gas. Obviously there would have been price changes and differences in seasonal temperatures to take account of to be able to give an accurate price comparison. But generally, if you can achieve an efficiency of greater than around 320% an ASHP should work out cheaper to run than a gas system. Plus you can get rid of gas standing charges if you get rid of your gas supply completely.

Feel free to ask any specific or general questions. I’m sure the members here will be able to help.

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You don't want to talk to me as I have all sorts of kit that no one in their right mind would fit 😆 It was fitted as part of a trial by OVO and their partners.

 

We have a Mitsubishi Ecodan ASHP which works fine. The running costs are about the same as our gas boiler. It works very differently to a gas boiler so we actually have a house that's warm for more of the time.

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Thanks for the info @M.isterW and @nealmurphy 

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Hi @Stevea 

I am part of the same trial as the other two, so don’t have direct experience of buying of a heat pump myself, but I know 2 friends who’ve had them fitted recently. I would strongly recommend using either a recommended installer (though even then there are risks) but in the current climate there are still cowboys (my first one) around, I can’t recommend enough using a heat geek approved installer. One of my friends used a heat geek installer, and whilst their system cost a little more to install, the quality of the install is far superior. 

Installation wise, I have plenty of experience. My first installer was one of the cowboys with months of trouble, the second install/fix was much like @nealmurphy’s experience and went well. 

Comparable running costs between gas previously, and elec only with my first winter using the heat pump, but read up on heat pumps, don’t try to run them like a gas boiler, eg on/off all the time, they work better left on a tick over. 

I now have a big battery, which charges from solar and off-peak, so running costs should be cheaper still. 

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Hi @Stevea I’m also on the government trial run by OVO. I didn’t get any opportunity to choose the kit that was installed, but I think it’s all good. It’s a small Daikin split system so the outdoor unit is just the compressor. The hydrobox, which includes the controller, is in the loft (which isn’t ideal). I have a Daikin room sensor which I believe is far preferable to having a third party thermostat as it can communicate allsorts back and forth…! Unfortunately more than I can remember. I also had all new radiators of which only one is huge, for our largest room.

The installation took some weeks (covid didn’t help there). The outdoor unit needs to have a good airflow around it so the expelled air doesn’t get sucked back in. That air is v cold so wouldn’t be much fun on a patio. 

Make sure your installer takes insulation seriously. They won’t be paying the electricity bill. My pipework is all in the loft so needed a lot of insulation - I upgraded what was supplied and will add more this autumn.

There were a few teething problems, one in particular revealed that the system can tell the 3 port valve to turn to hot water or heating, but if that valve fails there is no message coming back the other way. The house overheated in the night as the controller thought it was doing the hot water. We woke up sweating.

Performance-wise my system isn’t brilliant. I was getting a COP of about 2.5 on average. I know it could perform better than that. However the house was warm enough at 21 deg, and the cost was less than it had been previously.

My original heating was gas powered warm air and an immersion heater for hot water. I didn’t realise how inefficient both of those were until studying the ASHP and keeping records. 

I’m still learning about the best way to run it. The installers didn’t give me any guidance. They just said best not to touch anything. I only discovered how to set up the weather dependant curve last February. Come the cold weather I hope to get it running more efficiently. Something to look forward to 🙄

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Hi @juliamc Hi @hydrosam - thank you both.  Really useful info across the board. So useful for me :-)

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Hi All, just a few follow ups please. 

Did you follow-up on any references from the installers before using them?

Did you explore any installation financing options or leasing options?

Cheers again 

:-)

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Ah - the trial we’re on was funded by the government so all down to the Department of Business, Energy and Industrial Strategy. It was run by RetrofitWorks so I presume they chose our installers. 

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