Underfloor heating air-water heat pump. House too warm when the sun shines

Quite simple, without scripts...

Your suggestion would work, but it would almost always lead to the heating curve being raised late in the day until shutdown, since the current return temperature will usually be above the hysteresis band around the now lowered setpoint. And then there will be a heating pause lasting several hours in the late afternoon until the return temperature has dropped by twice the hysteresis value. Only then will it turn back on at full power in the middle of the cold night. I don’t know how much more efficient that would actually be, especially since at night I use slightly cheaper off-peak electricity and during the day, due to lack of photovoltaics, pay the full electricity price. With scripts, one could react a bit more flexibly.

Admittedly, the playful spirit is more the motivation here than the presumed 3 euros per heating month to be saved, which would probably be achievable only after a lot of optimization effort...

So a brief status update:

From the beginning of October until now: 140 kWh consumption
Heat meter shows 578 kWh
that results in a COP of 4.1

What can I say, we have 22.5 degrees everywhere, the system is running without any issues and is now extremely efficient. I am really very satisfied and also glad that the system is finally running satisfactorily.

I am now curious to see how much the COP will drop when we have temperatures permanently below 0 degrees.

Still haven't turned on the underfloor heating. The fireplace runs 16-18 hours when there is no sun. When the sun shines, the house heats up on its own through the window areas. I'm curious how much longer we'll continue like this. On the ground floor, it's currently 23.7 degrees, in the basement 20 degrees, and upstairs 20.5 degrees.

Does the fireplace heat the whole house? We can only heat the living area on the ground floor with it; unfortunately, nothing reaches the upper floor. Therefore, the underfloor heating has to be running, otherwise you would really be freezing upstairs. We also only heat with wood every few days.

We have rather small windows, I think that makes a big difference too. I see it with the neighbors, they still keep the blinds down during the day, probably because otherwise it would even get too warm...

Does the fireplace heat the whole house? We can only heat the living area on the ground floor with it; unfortunately, nothing reaches the upper floor. That’s why the underfloor heating has to be running, otherwise you would really be freezing upstairs. We only heat with wood every few days.

We have rather small windows, I think that makes a big difference. I see it with the neighbors; they still have the blinds down during the day, probably because otherwise it even gets too warm...

At least the fireplace is currently the only heat source in the house. Due to the open staircase to the basement and upper floors, I suppose it does have some effect, also through the chimney that runs through the upper floor.

What strikes me, however, is that an airtight (room air-independent) fireplace is incomparably less efficient than a room air-dependent fireplace. I once had a seminar in a farmhouse where there was an old wood stove in the middle; after one hour it was unbearable there. At home, the temperature upstairs with the fireplace on the ground floor never goes above 24 degrees Celsius.

We really have a lot of window area on the ground floor. The difference between sunny and cloudy is truly enormous.

The hardwood is not free either, but if I can do without the air-water heat pump for a total of two months in autumn, winter, and spring because of it, then it was worth it.

I personally find the 20 degrees Celsius in the bedrooms unusual, but they say it’s the optimal sleeping temperature for you, for whatever reason.

At least the fireplace is currently the only source of heat in the house. Due to the open stairwell to the basement and upper floor, I suspect it already has some effect, also through the chimney that runs through the upper floor.

What I notice, however, is that an air-independent fireplace is vastly less efficient than an air-dependent fireplace. I once had a seminar in a farmhouse with an old wood stove in the middle; after 1 hour it was unbearable there. At home, it never gets above 24 degrees with the fireplace on the ground floor.

We really have a lot of window areas on the ground floor. The difference between sunny and cloudy is really enormous.

The hardwood is not free either, but if I can skip the air-water heat pump for a total of 2 months in autumn, winter & spring, then it was worth it.

I personally find the 20 degrees in the bedrooms unusual but it is supposed to be the optimal sleeping temperature for you, whatever the reason.

I simply doubt whether you can really save with the wood. That really depends heavily on the respective prices and the efficiency.

COP including hot water? And do you now actually find the heat pump great?