Welcome

Before getting to an answer on your consumption figures can you just clarify what is the area of your home and construction of current outside walls.  What was the assessed heat loss.  How much oil did you previously use annually?

From what you have told us you are running it like a boiler, not like a heat pump.  This will cost more and you will be less comfortable.   You almost certainly don't need replumbing or indeed any new kit, nor is it likely that you need to take kit out, you probably just some adjustment to settings.

Your starting point should be:

• All thermostats/TRVs set to max (so they have no effect).  The exception may be the one on the controller depending on whether you have the R290 or R32 model
• Room influence/adaptive mode turned off on the controller
• Run 24x7. Use noise reduction mode/night time to deal with the night time noise issue you mention
• Adjust the weather compensation curve so your house is just heated sufficiently.  Make changes slowly, no more than once per day, this takes a few days but now is a good time to do it
• If rooms settle at different temperatures then balance the radiators on the LSVs to even out the differences.  Note that you use weather compensation to affect the overall temperature, radiator balancing to adjust the relative temperatures of rooms.
• Adjust your DHW settings so it heats once, max twice per day, to a max of 48C or better still less

Once its working stably with this done (allow a couple of weeks) you may be able to make some further tweaks to deal with solar gain/woodburners  however until you have done the above you may be operating very far from optimum both for cost and comfort. 

Thats a very brief outline and more detail/explanation can be provided if you wish to proceed.

The chances are that an Ideal Heat Pump owner will be along soon to give advice but in the meanwhile… You mention a 10kW battery then mention 4 kWh which suggests you have the ability to store 4 kW hours of energy at any one time; this might run a heat pump for several hours or so but unlikely to take you through the more expensive periods of a tariff. I use OE’s Cosy tariff and this provides a total of 8 hours per day at the lowest price and by charging my battery, I am able to run through from one cheap slot to the next. I am unsure how the Flux tariff compares with Cosy.

You would most likely find that setting that Honeywell ‘stat to high so that it doesn’t switch the heat pump on and off and using weather compensation to do the controlling would be a good move; I would encourage you to ascertain how the controller menus work and set it up soon. You are right about the increase in consumption in very cold weather and that it will improve when higher temperatures prevail. I’m sorry my advice is not specific, I don’t have an Ideal system, I’m with a Daikin monobloc but the general advice on using WC applies to the general principles of heat pump technology.

I feel sure an Ideal user will be along shortly to offer more useful advice though. Regards, Toodles.

@jamespa thanks for taking the time to answer. I guess I have to take the plunge and run the TRVs at max, seems so counter-intuitive! I think the problem with some of your other tips is that I really can't figure out how to do these steps - the Ideal controller is not that user friendly. I have already done the DHW timer on x 3/day. Haven't seen a night reduction mode on the Ideal controller or Evohome - does anyone know if they have this feature?

I don't have the exact area or heat loss data - do you think the installer design team would pass them on to me? 

Thanks again everyone 

And here is an Ideal HP290 14Kw user. Mine was installed in May 2025 so this is my 1st winter. I have a 180m2, 4 bedroom house of hybrid construction times. Using this forum I've learnt a lot about optimisation of the system.

I have a setback temperature of 18C from 2200 to 1500. I then raise the temperature to 19.5C until 2200. We have found any higher temperatures uncomfortable when sleeping. At -5C last week the higher temperature was reached and maintained. The house is warm day and night.

The Ideal is controlled by a Halo Lite connected to an Ideal control box - I have UFH which is controlled by a legacy Honeywell thermostat (which is due to be replaced any day now). The UFH is not a separate zone as such, just that the temperature is controlled by the Honeywell (and essentially set to the same times/temp as the rest of the house).

The Ideal Control doesn't offer much in the way of allowing you to alter the weather compensation. It's sort of on or off and I've left it as set. It seems to work. The flow rate is set to a maximum of 50C and there's no noise through our pipes.

Usage

Up to the end of December my overall utility bill (including EV charging) was 20% lower than the same period in 2024 i.e May to December.

My electricity usage (including EV charging) doubled in October, trebled in November and quadrupled in December. January looks like it might be a 20% higher bill than the equivalent gas bill in 2025. However, because my gas bill is now £10 a month, my overall utility bill over the same period will be about  17% lower. With gas heating we were generally only heating twice a day, once for 1.5 hours am and 6 hours pm.

Because I'm on IOG and have a battery (plus PV with very little sun recently) my cost per Kw was 13p in November and 16p in December. My CoP was around 3.4 in Nov/Dec but has taken a hit this month. I'm not bothered because it's the long term that's important - where we end up at the end of May this year after 12 months use.

And one controversial element - I've set TRVs in bedrooms to be at 3 or 4. The master installer technician from EDF said this was fine and any difference to performance would be marginal. All seems to work for me. 

Posted by: @cmartinbwmba

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@jamespa thanks for taking the time to answer. I guess I have to take the plunge and run the TRVs at max, seems so counter-intuitive! I think the problem with some of your other tips is that I really can't figure out how to do these steps - the Ideal controller is not that user friendly. I have already done the DHW timer on x 3/day. Haven't seen a night reduction mode on the Ideal controller or Evohome - does anyone know if they have this feature?

I don't have the exact area or heat loss data - do you think the installer design team would pass them on to me? 

Thanks again everyone 

It is counter intuitive but that doesn't mean its wrong.  All heat pumps work best if operated at the lowest possible flow temperature.  The amount of energy they need to deliver is set by the house, so the way to have them deliver the required energy whilst operating at the lowest possible flow temperature is for them to be delivering it for as long as possible and heating all emitters so that the output to the house at any given flow temperature is as high as possible. 

Oddly enough operating at the lowest possible flow temperature also leads to the greatest level of comfort!

Note that you have to combine setting the TRVs to max with turning down the Weather compensation curve.  Weather compensation settings are described on page 60 of the installation and maintenance manual here   I dont think you can change these from the Halo.

The night reduction feature needs to be on the ideal to be effective.  What it does is limit the compressor speed which keeps noise down.  Ideal call it 'silent mode'.  See page 63 (and doubtless others) of the installation and maintenance manual here  Again I dont think you can change these from the Halo.

Happy to help interpret the manual.

Note Im not an Ideal specialist so Im going on general principles.  These will apply but exactly how to program them on your controller is something I have to look up just as you do.  Its also possible that the Halo will autoadapt the weather curve if you turn up the TRVs in which case you might not have to change it yourself.  Someone else, eg @davesoa  may know for certain, I will probably try to look it up tomorrow but whatever the mechanism the objective is to get you house heated at the lowest possible flow temperature which means that as many emitters as possible need to be operating for the longest possible time.

Do you need to heat DHW 3x per day and what temperature do you heat it to?

Posted by: @cmartinbwmba

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I don't have the exact area or heat loss data - do you think the installer design team would pass them on to me? 

They should have provided this with the quote.  Never mind, what was your previous annual oil consumption - that will give a good idea of the loss.

Posted by: @davesoa

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And one controversial element - I've set TRVs in bedrooms to be at 3 or 4. The master installer technician from EDF said this was fine and any difference to performance would be marginal. All seems to work for me. 

Not so controversial - using TRVs is a minority of rooms, particularly upstairs ones, is not likely to affect efficiency markedly.  It does however affect engaged system volume which might cause problems with defrost and cycling, so turning bedrooms down on the LSVs is preferable but not essential in many cases.

just looked at the HP290 manual. 

Weather compensation- the manual states “do not change this setting from standard for optimum appliance operation.”

Silent mode - “should be switched off otherwise central heating and hot water operation is likely to be compromised.” 

This is a heat pump that is not designed for micro adjustments. Set it running and leave it be it seems to be the way. 

Posted by: @davesoa

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just looked at the HP290 manual. 

Weather compensation- the manual states “do not change this setting from standard for optimum appliance operation.”

Silent mode - “should be switched off otherwise central heating and hot water operation is likely to be compromised.” 

This is a heat pump that is not designed for micro adjustments. Set it running and leave it be it seems to be the way. 

With 'Standard' there are 8 different heat curves (temperature levels) available, I think the idea is that you can change between these (My Vaillant has a very similar concept), whilst still leaving Standard mode set!  Thats certainly how I read it.

The manual is right about silent mode, it may well compromise heating because what it does is reduce the max compressor modulation, which may mean it cant deliver max output.  However as a way to make it quieter at night (and given that @cmartinbwmba already accepts a setback) its potentially an option.  This is not the most important thing however, setting it back on the Halo may well be as good, depending on how exactly the Halo works.  The most important (for @cmartinbwmba) is to get the weather curve right (in standard mode) and emitters balanced.

Posted by: @davesoa

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Set it running and leave it be it seems to be the way. 

Definitely right, but only when first correctly adjusted!  We don't yet know enough about @cmartinbwmba s system to say whether or not it is for sure, but from what he/she has posted it seems likely not.

@cmartinbwmba You haven't told us yet what your oil consumption or assessed loss was.  However to answer indirectly your question about consumption, my December heat pump consumption was 650kWh.  My house loss is 7kW (measured) at the design temperature (which is -2 where I am).  I heat to about 20.5C.  My gas consumption annually was 18000-20000kWh, equivalent to 1800-2000 litres of oil.  The whole house is heated 24x7.

Yours appears to be roughly double, so if you are operating at the same efficiency which, given you also have an R290 heat pump, you should be (unless you are somewhere very much colder or you use a vast amount of DHW), your oil consumption would be expected to be 3600-4000l annually and your house loss at design temperature around 14kW.  From these numbers you should be able to answer the question 'Does this seem right'?

To be clear Im not a heat pump installer, Im just someone with a degree in physics - the sole value of which is that it helps sift out the BS - and who has been studying this stuff for 3 years, the first 2 years to inform my own install and the last year out of pure interest (and to return something to the community). 

I claim no expertise only a level of understanding.  @cmartinbwmba you need to make your own decision about what I suggest, but I can say that if you don't get your weather compensation parameters right, or nearly right, and operate with most radiators open, I can pretty much guarantee you will be paying more and be less comfortable than if you do.

@jamespa your opinions are always welcome and informed. In my case empiricism has shown I can achieve 20% savings over my previous utility costs and be much warmer than in previous winters by using standard settings. Others will no doubt have found that further experimentation achieves incremental results.

Posted by: @davesoa

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@jamespa your opinions are always welcome and informed. In my case empiricism has shown I can achieve 20% savings over my previous utility costs and be much warmer than in previous winters by using standard settings. Others will no doubt have found that further experimentation achieves incremental results.

@davesoa  Sorry I meant to tag and respond to @cmartinbwmba in my response, whilst nevertheless commenting on your comments for the benefit of @cmartinbwmba and in the context of his/her system.  Unfortunately I mixed things up and thus appeared to be commenting on your setup, which was not my intention.

I can see why, given what you have said about your system (you appear to be in a very different position to that expressed by @cmartinbwmba)  my post may have offended.  I have amended the post to help @cmartinbwmba but please accept my apologies for any offence caused by me getting you mixed up/tagging the wrong person in the text bas originally posted.  Hopefully I have now removed the source of offence.

@jamespa I wasn’t offended at all. You are very knowledgeable and I’ve used your advice a number of times to get my system where it is (often when reading what you’ve posted to help others). Keep on doing what you are doing.

Thanks everyone so much for your replies and help. Last night I took the plunge and removed all the Honeywell TRVs after setting the 4 zones to 24C. I had to remove them as they seem to whirr around of their own accord overnight even if you ask them to stay open or closed with temperature target commands. I then went into the loft (I don't have Halo) and did the following:

So essentially to gain control the code is 234 once you have pressed the three lines and right arrow together for three seconds. I then went here:

to make sure I had the right settings, and then here:

which is how I think one disables the room influence. I then set the weather compensation to 6 here:

and will see what happens. I guess I just use my own thermometer(s) inside the house to adjust the WC levels, and get to work on the LSVs slowly.

I also tried silent mode:

 - this seemed to simply turn the system off overnight and additionally probably made the DHW heating ineffective as there wasn't very warm water in the shower in the morning! So will stay away from this for now.

@jamespa I will try to get the design spec for more info. I would say I was probably using around 2000L/year on oil previously but it was mitigated by my using an immersion heater for the water during the day. I probably do have to heat the DHW at least 3 times a day as there are 5 of us showering/bathing/washing dishes throughout the day.

I've also had advice to move onto Octopus Cosy for now - fixed vs variable: I'd have thought variable better so I can switch easily to Flux in the summer?

Any thoughts on the above would be welcome, and I'll try and come back with some more info. I don't think I can engineer a 'setback' in my current setup? Correct me if I am wrong.