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Not a good January? My heat pump used 840 KWh of electricity

 
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Air Source Heat Pumps (ASHPs)
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 Potatoman
(@potatoman)
Trusted Member Member
Joined: 2 years ago
Posts: 57
Topic starter 02/02/2025 8:39 pm   [#2069]

Hi, this being my first winter with the heat pump, not sure what to expect with running costs. In January the heat pump used 840 KWh The property is a 120 sq meters Detached 4-bed dormer bungalow reasonable well insulated in an open aspect near Liverpool. How does it compare. Also, does anybody have consumption figures for this January and last January, this would give a comparison of how cold it has been.



   
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 Westkent
(@westkent)
Trusted Member Member
Joined: 3 years ago
Posts: 67
02/02/2025 8:57 pm  

Just compared the last 2 Januarys usage and they were more or less the same for me. 540KHw.

Not sure on my Sq meters tbh but it’s typically 3 bed semi.

Ecodan 8.5 with 8 Rads.

Im very happy with the system and expect better figures in the future as iv just replaced two very old outside wooden doors for two upvc doors that so far seem to make a good difference. 



   
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 Mike Patrick
(@mike-patrick)
Reputable Member Member
Joined: 5 years ago
Posts: 193
03/02/2025 9:03 am  

Not a good January for me:

image

All electric house so these are total kWh figures, not just ASHP

150 sqm 3 bed, detached fully insulated property with underfloor heating. These figures are why I know my system was badly designed and installed. But for now I've given up trying to find anyone I can trust to sort it out. I've previously spent  £ hundreds on heating engineers who come in and then prove to have no idea (including manufacturer recommended ones).

 

Mike


Grant Aerona HPID10 10kWh ASHP


   
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Morgan
 Morgan
(@morgan)
Noble Member Member
Joined: 5 years ago
Posts: 698
03/02/2025 9:24 am  

ASHP only for heating and DHW:

Jan 2024 - 786KW

Jan 2025 - 962KW

It leaves me thoroughly unimpressed.


Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
14 x 500w Monocrystalline solar panels.

2 ESS Smile G3 10.1 batteries.
ESS Smile G3 5kw inverter.


   
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JamesPa
 JamesPa
(@jamespa)
Illustrious Member Moderator
Joined: 3 years ago
Posts: 4714
03/02/2025 9:38 am  

Posted by: @morgan
↑

ASHP only for heating and DHW:

Jan 2024 - 786KW

Jan 2025 - 962KW

It leaves me thoroughly unimpressed.

 

You don't say where you are, but I checked the climate for January in central England Jan 2024 vs Jan 2025. 

Jan 2025 was significantly (16%) colder than Jan 2024 (as measured in degree days), so the difference is pretty much what you would expect allowing for the non-linearity of heating consumption vs OAT.  It appears that your grievance may lie with the Almighty not with your heat pump or its installer!

 


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.


   
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 IRMartini
(@irmartini)
Estimable Member Member
Joined: 2 years ago
Posts: 80
03/02/2025 10:15 am  

860 kWh (just ASHP usage)

155sqm 4 bed detached in Shropshire


“Anything worth doing, is worth doing right.”


   
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 Judith
(@judith)
Prominent Member Member
Joined: 2 years ago
Posts: 519
03/02/2025 10:20 am  

Ours used 993kWh of electricity for heating and DHW in January. As below a7kW Vaillant heating a190m^2 house, (1950s) with supplementary wood burner use on a handful of days. House heated to 20-21C.


2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with SCOP 4.7) open system operating on WC


   
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JamesPa
 JamesPa
(@jamespa)
Illustrious Member Moderator
Joined: 3 years ago
Posts: 4714
03/02/2025 10:40 am  

1022kWh here, 200sq m detached 1930s property with piecemeal fabric improvements, loss ~7kW @-2.  Figure is from the (Vaillant) heat pump itself not independently measured, but consistent with my metered total consumption of 1377kWh (which includes some EV charging).  COP of 3.7 claimed by Vaillant app which I have no way to validate.

For anyone doing year on year comparisons, January 2025 was a lot colder than Jan 2024, certainly in Central/Southern England.  According to degreedays.net Birmingham(UK) Airport registered 16% more heating degree days Jan 2025 compared to Jan 2024.  This would likely translate to an expection of ~20% more consumption given the nonlinearity of ASHPs.


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.


   
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 Mike Patrick
(@mike-patrick)
Reputable Member Member
Joined: 5 years ago
Posts: 193
03/02/2025 11:26 am  

Yes, it was much colder this January than in 2024.

My own daily measurements show it here in West Oxofordshire.

Dotted lines on the chart are last year, solid lines are current year.

It shows very clearly that as temperature falls, kWh increases (a lot)

Mike

 

image

Grant Aerona HPID10 10kWh ASHP


   
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cathodeRay
 cathodeRay
(@cathoderay)
Famed Member Moderator
Joined: 4 years ago
Posts: 2886
03/02/2025 11:31 am  

My figures for Jan 2024 and 2025 (only years with complete data, smallish three bedroom cottage):

Jan 2024 Mean OAT 6.02 degrees, All ASHP 1591.14kWh, Space heating ASHP 1554.67kWh

Jan 2025 Mean OAT 4.85 degrees, All ASHP 1884.71kWh, Space heating ASHP 1849.01kWh

Defo not a good January in 2025 ... Colder OAT will explain some, possibly most, of the difference, but whatever the cause, still painfully expensive.

 

Edit: I've just checked the mean IAT: Jan 2024 18.65 degrees, Jan 2025 19.16 degrees. Good news is that my heat pump on average maintained my IAT at my desired IAT (19 degrees) in 2025, but of course that extra half a degree over Jab 2024 will also have increased running costs.   


Midea 14kW (for now...) ASHP heating both building and DHW


   
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Morgan
 Morgan
(@morgan)
Noble Member Member
Joined: 5 years ago
Posts: 698
03/02/2025 11:43 am  

Posted by: @jamespa
↑

Posted by: @morgan
↑

ASHP only for heating and DHW:

Jan 2024 - 786KW

Jan 2025 - 962KW

It leaves me thoroughly unimpressed.

 

You don't say where you are, but I checked the climate for January in central England Jan 2024 vs Jan 2025. 

Jan 2025 was significantly (16%) colder than Jan 2024 (as measured in degree days), so the difference is pretty much what you would expect allowing for the non-linearity of heating consumption vs OAT.  It appears that your grievance may lie with the Almighty not with your heat pump or its installer!

 

@jamespa

I don't dispute the difference in temps. I'm generally unimpressed with the overall consumption.  I don't dispute that this January has been much colder than last.  So actually my grievance is with the consumption and the fuel price.  I live in rural west midlands, UK.

 

 


Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
14 x 500w Monocrystalline solar panels.

2 ESS Smile G3 10.1 batteries.
ESS Smile G3 5kw inverter.


   
ReplyQuote
 Boylips
(@boylips)
New Member Member
Joined: 3 years ago
Posts: 6
03/02/2025 11:53 am  

Posted by: @potatoman
↑

Hi, this being my first winter with the heat pump, not sure what to expect with running costs. In January the heat pump used 840 KWh The property is a 120 sq meters Detached 4-bed dormer bungalow reasonable well insulated in an open aspect near Liverpool. How does it compare. Also, does anybody have consumption figures for this January and last January, this would give a comparison of how cold it has been.

 



   
ReplyQuote



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