We have had our heating off for the last month or so.  Solar gain definitely warms us up during the day.  The coldest days have resulted in 16C in the morning - which fairly quickly rises to 18 so perfectly comfortable for morning routines.  Our bedroom window is open overnight and occasionally a few minutes of a fan heater is deemed necessary.  By mid afternoon the house is at least 20C most days and normally no more heat is required before zzzzzs.  Like you, we are in our first year of ASHP living and experimenting.

Posted by: @l8again

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As a new HP owner, I would welcome people’s opinions on whether it is better to turn space heating off during the summer or to leave it on? Solar gain can leave the house very warm overnight and my wife likes to sleep with an open window.

We turned it off a few weeks ago then turned it back on again.  Im expecting to turn it off again.  Our house exhibits similar behaviour to that described by @davidb  

My heat pump (and yours, we have the same) has various parameters like 'max outdoor temp for heating' and the possibility to operate in a 'limited' mode (where it shuts down if the IAT is more than a certain amount above the set target - room temp mod - expanded).  I strongly suspect that these could be combined to 'automate' the shoulder season on/off decision, or indeed the whole year on/off decision.  Can I be bothered - probably not.  My boiler didn't have anything like this level of sophistication so I used an on/off switch, judging whether overnight cooling would most likely be countered by daytime heating.  Sometimes simple is sufficient.  But if you are interested these are the parameters I would start with.

Thanks both. I have turned my heat pump space heating off and we will see how it goes over the coming week. I am sure that my wife will be happier and the saving of less than 10p a day (EV tariff plus battery) cannot be ignored!

Thinking ahead, I guess that turning it back on earlier than one might do with a gas boiler is something to bear in mind.

Posted by: @l8again

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Thinking ahead, I guess that turning it back on earlier than one might do with a gas boiler is something to bear in mind.

Personal choice but without a doubt my heating pump copes better with the season ends than my boiler did.  The boiler just overheated the house or caused the themerature to swing a lot, so I turned it off because slightly cold was better than boiling hot.

Posted by: @l8again

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As a new HP owner, I would welcome people’s opinions on whether it is better to turn space heating off during the summer or to leave it on? Solar gain can leave the house very warm overnight and my wife likes to sleep with an open window.

I only switched ours off yesterday.

As the nights were a little chilly, it was nice to wake up to a warm house.

During the day it switched itself off as I set it to only run when when the OAT was above 15c.

Tracking the consumption it didn't seem worth it to save about 10-20p a day and have a chilly house to wake up to.

@bash Likewise, I only flipped the heating toggle switch off yesterday; the pump has been running now and again (mainly at night) to keep our home at our preferred comfort level of 22.5 deg. C). This has meant we have used 3 or 4 kWh of solar generated power per day over the last few weeks. With any luck, the heat pump may now zzzzzzzz for some months. Regards, Toodles.

Posted by: @toodles

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@bash Likewise, I only flipped the heating toggle switch off yesterday;

May 22 and finally heat pumps will be going off full-time for heating... hopefully till as late as possible to make up for the coolish spring.

Posted by: @bash

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...

I only switched ours off yesterday.

...

Mine's still on and will stay on throughout. However, it is set to prohibit any home heating whenever the OAT is at or above our preferred internal temperature, so going to the controls and turning it off is only a symbolic exercise anyway.

Is there anyone here on the forums with an Air-2-water heat pump using it for cooling purposes during the upcoming heat-wave?

Posted by: @temperature_gradient

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Is there anyone here on the forums with an Air-2-water heat pump using it for cooling purposes during the upcoming heat-wave?

Yes - we use our Mitsi 14kW unit for cooling.  I have just switched it over in anticipation of the hot weekend temps.

We have benefitted from "light cooling" since it was installed in 2023, but only in conjunction with our Jaga Strada fan-assisted rads.  I have described these elsewhere, but basically they have finned emitters like a car radiator with multiple fans which move the air through the emitters.

Provided we keep the flow temp above about 16C condensation is not a problem - at least on the typical British dry summer day.

Our system was originally plumbed with a 4 port buffer, and we had an issue with the HP cycling every 10 mins or so when on cooling.  This was due to the chilled water settling at the bottom of the buffer and returning directly to HP without going around the secondary circuit.

Earlier this year I had the buffer repiped as a volumiser (on the flow side) and so far, this seems to have fixed the cycling problem. 

Posted by: @temperature_gradient

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Is there anyone here on the forums with an Air-2-water heat pump using it for cooling purposes during the upcoming heat-wave?

Yes

I use the LG to cool the slabs with underfloor heating. It works fine, as mentioned above flow temp needs to be high enough to avoid condensation.

This lowers the ambient temperature in the house but it does nothing for humidity, so if relative humidity gets too high I need to use a mobile AC unit, because the fan coils are not installed yet.