Help please...heatpump costing me £600 electric bill per month


I badly need some help / suggestions asap.

Mine is a 5 bed semi house (tbh its not massive as bedrooms 3 & 4 are box rooms & the 5th one is loft room)
I got 20 Solar panels already on the roof (installed May 2022).
I got underfloor heating on the ground floor and standard radiators upstairs powered by gas boiler, all was working well without problems.
Then I got this idea (terribly bad) of getting heatpump and replace my gas boiler. I got this done with Omni Heat&Power in Aug 2022.

I was of the impression that my bills will be <£200 per month.
The underfloor seems working well, but the upstairs is not getting any heat at all. The radiators are always cold. But my electric bill sky rocketed to £600+

Unfortunately for me Omni Heat&Power gone bust in Nov 2022. And I am left with not much help.
There is a 50K insurance something, I spoke to (insurance guys). I was told to get someone to check the system and give a quote for what needs doing to rectify.

I am totally lost and struggling.
Any help / pointers on this please.
Also want to know if I can use my solar batteries to source the heatpump. (I was of the impression it was done that way, but I doubt)

I just checked and noticed that it is costing 1KWH in 30minutes

Apologies for the long post

Thank you


If you don’t get any help here, you might do better posting this on the Build Hub forum. There are a lot of people on that forum that have installed heat pumps and they might be able to help →

Another source of help might be Heat Geeks, I think that was the name someone mentioned, as being people who could check the system and give advice about what needs to be done to fix it.

If you want a long read, then there is a recent post on here about issues with an installation that doesn’t look good and where the installer went bust.

If you get things sorted and then want to monitor performance then there’s a wealth of information and help here on this forum.

Best of luck.



Here’s the very long Topic that Simon is referring to. It is very repetitive in places.

Hi Venkat, welcome to the forum.

Rather than trying to diagnose over the internet, I think you should prioritise finding a “local expert” who can come and have a look and give you the quote you need to get any money from the insurance company to rectify the problems.

I would do this quickly as insurance money like that can get used up.

FYI, my heat pump can easily consume 1kWh in 30 minutes, it used 5.9kWh in one hour at 2am this morning however these highest consumption rates are typically when outside temperatures are below zero. You clearly have something wrong as your upstairs isn’t working correctly.

Edited for autocorrect blunder
Edited again; if you are in Kent I would be happy to give you my installer’s info to review your system.

Hi and welcome.

Sadly this is too often the case.

The first question is what data are you able to extract from your system to try and determine what is happening. Data is very much King.

Do you have any other devices such as Heat Meter, Power meter Thermostats or controllers specifically for the HP?

If you list all of the equipment installed including the HeatPump and any remote montoring systems you may have been signed up to, then search on here for those specific items, that would be a good start.

Do you have a design diagram? If so upload that and list your equipment as a starting point.

What is your level of tech/computer experience/skill?

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If you can list what you have installed, eg cylinder, controls, back up heater, timings, pictures would help.

They may be if you are on payments averaged out over the year, but more than half the electricity will typically be used in December, January and February, so it can look very uneven and scary if you aren’t. Also, all prices increased a lot last autumn and some a little on 1st Jan, so the figure will be higher than estimated last August before the Truss ministry.

Other comments above contain good advice.

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New to this forum. I am not an engineer just
someone who had a ASHP fitted in our 1960’s well insulated, detached house 6 months ago by Octopus.
As the cold weather started in late November, our electricity consumption soared like yours, frequently hitting 8-9 kW when it had been 2-4 kW max. I deduced the booster heater was kicking in and called out the Octopus service engineer. They found this to be so. The booster
heater had been set to kick in at +5C instead of -5C. They altered this and the system has run well ever since.



And they of course compensated you for their error :upside_down_face:

Yes Octopus compensated me for their error.


TBH not that surprised, but wow anyway! :clap:

Sorry for the delay, was out of station.
Here are pics of my system

Apologies for the delay in replying as I was out of station.

I do not have good knowledge on this heatpump setup.
But can try and follow any instructions if available. Also how to monitor the usage I am not sure on this either.
I got solar in the house as well, for the heating we got heat miser thermostats and operated mostly via mobile app.

Here is the list of items installed.
Also the system pics are in the below post.

  1. Cylinder
  2. expansion tanks 2 (red and white)
  3. Defrost tank
  4. Mega clean
  5. Grant circuit box
  6. Grant small box for the settings (11 & 12th pic)
  7. one motor of some sort below the kitchen sink(13th pic). This one turns on when ever it lies and costing me electric bill.

Also I got solar in my house with 20 panels, lately I noticed that the installation guys did not even bother using the batteries even for the electic supply to heat the water in the water tank.

I have contacted several people to come have a look and tell me what needs doing and to fix it
No one are insterested to come as they think its a small job or its not going get paid more :frowning:

Even when I turn on for hot water it is costing like 6 to 8 Kw for 2 hrs.
I am bit confused on this now.

Try Heat Geeks They get a good rep.

Do you have a system diagram?

What of this was fitted with the HeatPump?

So the grant heatpump uses 3rd party controls so there is no hot water priority so it is possible to have your heating and hot water on together. I have a grant heatpump, how confident are you in accessing the control panel and changing the parameters.

I think I can as I did once with the Grant customer care guys

As others have said, Heat Geeks are very helpful.

In the meantime here are acouple of tips.

The ‘engineers’ who fitted your system probably set it to operate at a set flow rate as that is easiest for them to set up. It’s also the most expensive and wasteful for you. This is what happenned to me and it took me a while to sort it as my installers went bust, too! They also probably set the flow temperature too high for your needs which will be costing you money unnecessarily

Set it to Temperature Compensation Curve with the max temp as low as is comfortable. This cut my electricity consumption in half.

Next, sort out all your draughts: windows, doors, letterbox, keyholes (I kid you not). This makes a surprising difference to cost and comfort.

Contact Heat Geeks who will be able to give you further advice about optimising your system.

I have learned that heat pumps are great but the people who fit them are often woefully inadequate at optimising a system.


Looking at this picture it seems that your immersion heater is ON (green light on the timer, and switch set to permanently ON. If it is left in this state then you will be wasting a lot of electricity heating your hot water with the immersion instead of the heat-pump.
What part of the country are you in - if in or around Berkshire I can help asses the installation

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Hi Frankie,

I manually turn it on once a while to use the immersion heater.
Its generally off.
I am based in Slough SL3.
Would be of great help if you can help me