Ground Source Heat Pump Costs

Sarahfj

Hello, we installed a heat pump some 13 years ago, but we are now paying the price of its high electricity demand - 23,000 kwh per year. We simply will not be able to afford to use the underfloor heating this winter, and I'm worrying that we might not be able to afford to have it heat our hot water either. Would heaters at sinks/basins be more affordable? and if I could switch my heat pump off overnight would it damage it? Ours is an older model that doesn't let us decide when it should come on, but it would be more affordable if we could use it in conjunction with our small Solar PV system and there would be some hope of affording it. At the moment it keeps coming on in the nighttime. I am terrified as ALL my income will be used on just our electricity after Oct. I've spoken to my heating engineers with no concise help. Any advice please?

QrizB

23000kWh/yr seems quite high. What's the make and model of the heat pump? Can you give some general details of your property?

There are some experienced heat pump users on the for, including @Mstty @Reed_Richards and @shinytop (apologies to those I've not tagged). I'm sure they will be able to help you reduce your energy use.

ProDave

If you are using that much with a heat pump, the one thing you can be sure about is direct electric (resistance) heating will cost even more.  The basic problem is likely to be a poorly insulated house.

How many kWh is it using per day or per week at the moment just heating hot water?

Mstty

Hi and welcome to the forum.

Thanks for the tag @QrizB

Firstly 23,000 kWh is a heck of a lot so has this always been this high and if not what was your lowest yearly figure?

Firstly some basics could you answer the following this will all help

1) do you have separate electric heaters you use

2) any electric showers

3) air con units

4) electric vehicle

5) any desktop computers/servers etc

6) how many fridge freezers and are any double door American type ones

7) how often have you had your ground source heat pump serviced or do you do it yourself and when

8) how many people in the house

9)how big is the house, how many bedrooms and is it large of small for that amount of bedrooms

10) age of house

11) any additional insulation you have had done probably in conjunction with the GSHP

12) make and model and controller details on the GSHP

13) do you heat your water constantly

Reed_Richards

With a GSHP you should be able to achieve a SCOP comfortably in excess of 3, but let's be pessimistic and say its just 3.  That would mean your 23,000 kWh per year of electricity should be giving you at least 69,000 kWh per year of heat.  That's over 3 times the heating requirement of the 4-bedroom bungalow where I live so either you live in a very large but poorly insulated dwelling or there is something very badly wrong with your heat pump.  If it's the former then I'm afraid the rise in electricity costs means you are now living beyond your means.  If it's the latter then you need new heating engineers because the ones you have at the moment are letting you down badly.  

ccbrowning

How big is your house? I estimate I'm looking at around maybe 10,000kWh per year in our 4 bedroom, 2100 m2 house for all of our electricity, including the GSHP. Is it possible to have the GSHP itself hooked up to an external timer?

Cardew

ccbrowning said:

How big is your house? I estimate I'm looking at around maybe 10,000kWh per year in our 4 bedroom, 2100 m2 house for all of our electricity, i

That is a big 4 bedroomed house at 22,604 square feet!

Walter_Sobchak

Hi all
 
We have a GSHP in our 4 bedroom recentish new build.

We used 9851 kWh in 2019, 10537  kWh in 2020, 12450 kWh in 2021 (we bought a hot tub in May that year, which is being switched off once our fixed 20.04p deal ends Sep 23)

We only have ours on in our large kitchen diner and on low in the bed rooms when its below 0 outside.    

Surely you must have thermostats to regulate when it comes on and off ? can't you just adjust them?

Reed_Richards

I have an ASHP heating a 4 bedroom bungalow with radiators, built in 1980.  It used 6930 kWh in its first year of operation and is on target to improve on this in year 2.  I would have expected that a GSHP would use less energy than an ASHP and a modern 4 bedroom dwelling would be better insulated so require less energy to heat it than my bungalow.

Edit;  Don't know my internal floor area but the plot area is 192 m2 measuring the external walls and excluding the porch.  EPC states hot water and heating requirement is 21,000 kWh per year, oh and I see EPC states 168 m2 internal floor area.   

Mstty

ccbrowning said:

How big is your house? I estimate I'm looking at around maybe 10,000kWh per year in our 4 bedroom, 2100 m2 house for all of our electricity, including the GSHP. Is it possible to have the GSHP itself hooked up to an external timer?

Our house 180m2

The EPC suggests around 11,000 kWh of heating and hot water required from our ASHP 

In the last year (our first year) 4250 kWh so if we take that 11,000 kWh at face value gives us a cop of 2.6.

2015 built high B on energy rating we moved in 13 months ago and could see bigger savings this year as we have a year's worth of knowledge now and energy reduction exercises to try. We expect to use 3750kwh in our second year for hot water and heating from the ASHP bringing the COP to 2.9 with a reduction in temp by 1oC and use of the weather compensation curve rather than me manually fiddling every day lol.

Mstty

I do hope the original poster returns with more info