@newhouse87, most owners in the UK would settle for anything over 3. We’re at 2.7. There are others on these forums running over 4 on weather compensation with good insulation. See if you can tweak things this autumn and aim for 3.5.

@editor I presume mine would even be higher i could discount dhw? Was running 2 dhw cycles a day for first 9months in the house last may, now know that 1 in middle of the day is enough.

Posted by: @newhouse87

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Was running 2 dhw cycles a day for first 9months in the house last may, now know that 1 in middle of the day is enough.

User experience will vary, of course, depending on:

• the capacity of the DHW storage
• the number of people in the household drawing on that water

Those issues should've been brought into the calculations when the system was first designed.

Although we didn't have a heat-pump, I noticed a considerable drop in our DHW requirement once our teenage daughter left home! 🤨 

Yeah just presuming a cycle less day and also in middle of the day would help cop a little bit. It will be next winter when i get to try derek m suggestions for weather compensation and running low temp all the time. Heating hasn't came on in 4 days now as im also using set back mode at night time on the only programmable stat i have that is running the whole house now as i opened all loops as per suggestions here.

aargh,this heatpump is the bane of my life.

Essentially noticed my energy usage spiking in middle of night even though no call for heat as im using setback,6kwh usage at 4am last friday. 4am few hours ago i woke up to fan, got up, flow going through all open loops even though no call for heat. I switched off all stats, still flow 30l/min. then switched off unit, still flow. Had to go outside and switch emergency stop to stop flow. switched back on and flow started again. 3 hours now and still running and no call for  heat. WTF is going on? any advice much appreciated. Doesnt spike evey night.

@newhouse87

I would suggest that you check through all the settings within the controller, to see what, if anything, is being switched on.

@derek-m i didnt alter any settings other ten basic stuff with dhw temp etc for this to start happening though. All i know is flow is going to the open loops,lwt is increasing and fan outside is on. 6kwh usage in a hour seems v excessive at4am too.

Posted by: @newhouse87

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@derek-m i didnt alter any settings other ten basic stuff with dhw temp etc for this to start happening though. All i know is flow is going to the open loops,lwt is increasing and fan outside is on. 6kwh usage in a hour seems v excessive at4am too.

What are all the readings on the controller telling you? Have any sensors failed?

@derek-m n

o error messages, i switched off on main panel an hour ago and switched back on and now flow has stopped, earlier it seem possessed. Rare if ever i had 6kwh usage in a hour.

Are those yesterday's readings?
Or last Friday's?

What 'event' occurred at 8am which might account for the sudden drop in electricity usage?

Posted by: @newhouse87

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@derek-m n

o error messages, i switched off on main panel an hour ago and switched back on and now flow has stopped, earlier it seem possessed. Rare if ever i had 6kwh usage in a hour.

Did the outside temperature actually go below zero?

Do you have a backup or booster heater installed?

Check through all the controller settings to see if any mention frost protection, backup heaters or the like.

@transparent thats last friday, id imagine heat pump switched off, i have v low usage when its not running. them figures seem v high, the heating wasnt meabt to be on and it wasnt that cold so reckon its the same thing that happened this morning but i wasn't aware of it last week.