Heat Pump Sizing & Installation Costs
I’m doing some research for an upcoming article and podcast, and I’d love to gather some data from our homeowners on the forums that have installed heat pumps. If you’re willing to share, it would be massively helpful!
What I’m looking for:
• Property size (in square metres)
• Heat pump size (in kW – e.g. 5, 6, 12kW, etc.)
• Approximate installation cost (heat pump, labour, etc.)
If you’re happy to share your figures publicly, please post them in this thread. If you’d rather keep the cost private, feel free to DM me or email me at editor@renewableheatinghub.co.uk
Info sent to me in private will be kept confidential and will only be used for statistical purposes.
Thanks in advance to anyone who contributes.
Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb
Subscribe and follow our Homeowners’ Q&A heat pump podcast
Perhaps useful to have installed date too? To get context...my example:
LG Therma V 16kw monobloc
Installed Aug 2020 replacing oil
Approx £12k. Included replacement hot water tank and one radiator. RHI grant
200 sq m (100 sq m listed building, poor insulation. + 100 sq m modern extension with excellent insulation). Underfloor heating downstairs throughout.
Listed Grade 2 building with large modern extension.
LG Therma V 16kw ASHP
Underfloor heating + Rads
8kw pv solar
3 x 8.2kw GivEnergy batteries
1 x GivEnergy Gen1 hybrid 5.0kw inverter
Manual changeover EPS
MG4 EV
2024
200sqm
7kW
200l UVC
2 new rads, one new fancoil, one existing rad relocated (total 4 rads changed)
16A feed for heat pump already in place so not included
£12,450 less grant = £4,950 net
Work duration - 6 man days of approx 9 hours each
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
2019
180sqm timber frame
14kW
300l DHW
16 new rads K2 and K3, new delivery pipework, new electrical consumer unit
£12,200 less RHI (Scot) £13,200 over 7 years
6/7 days for 2 heating engineers and 1 sparky
1970s 4-bed detached house approx 168 sq.m internal area in central southern England. Approx 200mm of roof insulation, insulated cavity walls, fairly recent double glazing including a 3m wide two storey north facing widow which is triple glazed but a heat loss due to its size (big curtain closed in autumn and opened in spring).
£16,600 for 7kW Vaillant Arotherm+ heat pump including SENSOcomfort controls, SENSOnet gateway, Telford Tempest 250 litre combined DHW cylinder / buffer tank and 11 new radiators.
Installation took about 20 person-days of work. There was significant pipework modification to accommodate larger radiators and one new radiator and probably above average work to connect the heat pump as it was two rooms away from the cylinder (placed in what I considered to be the most convenient location).
I suspect I paid a generous price but it was the only convenient quote from an installer who appeared to understand the technology and I wanted the work done during the summer (Octopus offered a lower price but with a likely installation well into the autumn and would only change such radiators as they deemed necessary). Radiator replacement was steered by both the heat loss calculation which I compared with my own estimate, my knowledge of where more heating was needed and my desire to replace all radiators which weren't 21st century. The work was done competently and fitted in with my own needs such as radiators were removed and I was given a few days to do decorating before new ones were fitted.
The 7kW sizing seems to be correct. The maximum hourly output so far according to the Vaillant app was 7.6kW for 7 to 8am on 11th January when the outside temperature was -7C and the heating had been turned up after a modest overnight setback. However, I suspect that Vaillant are over-estimating the output as a daily COP of 3.9 for that day (mean temp of -3.7C) is almost implausible. Nonetheless, generous radiator capacity keeps the flow temperature below 40C under the worst conditions.
More details of the work are attached.
Ours is a 1930s bungalow with extension and loft conversion and is now about 105 sq m. Generally well insulated but we did replace french doors, front door and two small kitchen windows that were all found to be losing more heat than they ought.
We replaced our oil boiler with an 8.5kWh Mitsubishi Ecodan in December 2021. No radiator changes were needed but there was a reasonable amount of pipework needed replacing with wide bore pipework and a new hot water tank was installed as well. They also had to install a separate sub board specifically for the heat pump to avoid tripping the switch on startup (which it initially did intermittently). In total it cost £15k inclusive of the vodka and tonic, but given the RHI it came to a net cost to us of about £4k. The guys spent about 5 days on site including the troubleshooting that eventually led to the installation of the sub board.
The subsequent three years or so have shown a number of areas which are frequent forum bugbears that our guys did right unbeknownst to us (newbies that we were back then). No red flags were raised then nor any since and our bills have dropped markedly as a result.
I should also say we then opted for their 5 year maintenance plan for another £950 hence a squidge under £200 per year which has subsequently been shown to be reasonably good value, particularly since each time they've turned up to do the servicing I've seen them actually working for their money rather than just tinkering. Is it money for old rope? Probably. Is it a rip-off? At that price and given the attention they show, no. Are we satisfied? Absolutely.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
- 22 Forums
- 2,052 Topics
- 44.7 K Posts
- 50 Online
- 3,282 Members
Join Us!
Trusted Installers
Struggling to find a reliable heat pump installer? A poor installation can lead to inefficiencies and high running costs. We now connect homeowners with top-rated installers who deliver quality work and excellent service.
✅ Verified, trusted & experienced installers
✅ Nationwide coverage expanding
✅ Special offers available
Latest Posts
-
RE: Tariff and charging strategy advice please
@johnmo I have tended to regard the solar element of th...
By Toodles , 48 minutes ago
-
RE: Warm weather and heat pumps.
Ours is also still on. Heat pump kicks in a bit at nig...
By JamesPa , 4 hours ago
-
RE: How to disable radiator heating in LG HM161MR
Just to add to above,when adjusting WC heat pump should...
By JamesPa , 5 hours ago
-
@johnmo yes I can believe that. It seems to be human na...
By SUNandAIR , 9 hours ago
-
RE: Help optimising my system!
I would be doing things a little more simply. Your heat...
By Johnmo , 10 hours ago
-
RE: Yes, the "zoning with ASHP" topic again...
@johnmo Thanks, Johnmo — fair points as always. I ...
By HarryRea , 10 hours ago
-
RE: Renewables & Heat Pumps in the News
If you want to read a huge amount of speculation, fabri...
By Judith , 23 hours ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
@andris hi. Whilst I understand your logic, the FiT is ...
By JulianC , 24 hours ago
-
-
IVT Greenline high pressure switch and electrical cassette errors
I have an IVT Greenline HT Plus C heat pump that is con...
By tdudgeon , 1 day ago
-
RE: Volumisers in Heat Pump Systems: Does Placement Matter?
Not sure if you have the defrost cycle and what happens...
By Johnmo , 1 day ago
-
RE: Hydronic plinth heaters and ASHPs
Thanks. I suspected I was overthinking that part. ...
By benson , 1 day ago
-
RE: Additional Battery v Wind Turbine v Ripple
There was a call today for Ripple investors and amongst...
By Judith , 2 days ago
-
-
RE: Commencing on an ASHP Installation Process
I think you may very well be right and of course A2A ca...
By JamesPa , 3 days ago
-
-
RE: Agile: average import cost vs other tariffs?
@old_scientist We are with SSEN and our G99 application...
By Toodles , 4 days ago
-
RE: ASHP Ecodan L9 error - No Heating but Hot Water
@phoenix15, @heacol cover your area… I’d strongly recom...
By Mars , 4 days ago
-
RE: Potentially more choice including air to air heat pump grants
@jeff Such documents are far too wordy for my ‘daily re...
By Toodles , 5 days ago