Geothermal heat pump single-family house 200m² underfloor heating kfw55 - setting/optimization

Hallway



Bedroom



Bathroom (however, after 10 minutes of intensive ventilation)



The trick here is the hysteresis of the thermostats. I lowered it from 0.5 to 0.2°C, so that enough heating circuits are practically always open to ensure sufficient underfloor heating flow. Of course, the actuators open and close several times a day, but the comfort is worth it to me.

As wrote, you should find out what the heating curves of the mixer and heat pump are and post them here.

This is probably a stupid question but can you tell me "what that is"? Or I’ll try it myself and you correct me? The heat pump heating curve is the one where, at the temperatures of the set sensor, the heat pump compresses. It switches on when the set hysteresis is undershot downward and off when it is exceeded upward. If you mean that: I currently have it set to fixed value return flow control. Until last night at 28 degrees (with 2 setback times) and 4 degrees hysteresis. I didn’t think that was bad, although the return and supply after the heat pump running times (during which the supply was heated to about 36 and the return to 28+4 degrees – and that with "weird" bumps in the heating curve) immediately dropped back to 27/28 degrees and it then took about half a day until the return dropped to 28-4 degrees. Heating curve mixer: I can’t find anything about that in my documents. I can set a mixer hysteresis and a mixer runtime on the heat pump. Hysteresis is 0.5 K and runtime 2 minutes. According to the heat pump description, that is the standard. What do I change with that? Am I right in assuming that this means that when there is a 0.5 K spread between buffer water and supply, the mixer runs for 2 minutes and mixes warm water into the heating circuit?

What do you still want to optimize with 8kWh per day and 2 compressor starts? You have the desired temperatures in the rooms, have ERR active, a buffer + mixer. In my opinion, there is nothing more to get out of it at the size of your house...

Maybe you can just set a heating curve that then applies to both the heat pump and the mixer... Take a photo of the setting of your heating curve. It is also important where your return sensor is located. Is it directly on the return or in the buffer?

what do you still want to optimize with 8kWh per day and 2 compressor starts? You have the desired temperatures in the rooms, have ERR active, a buffer + mixer. In my opinion, there is nothing more to get out of it at the size of your house...

hmm. I would have gratefully accepted that as a compliment a month ago. But now I have learned that the neighbor in the new building, with an air-water heat pump and the same storage (only 850 instead of 650l), managed February last year with under 7kWh/day. And the average temperatures were simply more than 6 degrees lower there. His house is not much smaller. I think the heated/warm area is similar. I don’t know if he has 2 bathrooms and I don’t know if he has an additional heater in the bathroom. I’m trying to find that out. Basically, it’s mainly about understanding the system well for me. Unfortunately, my heating installer is not able to do that and I also don’t think it is his obligation to initiate me into the absolute depths. Can you still answer me how you regulate that in the bedroom? Do you have the valve standardly opened by your ERR at 0.2l/h or is it standardly closed and only opens if it should actually get too cold in the bedroom?

Comparing yourself to others only makes you confused. The heating consumption strongly depends on the desired temperatures. For a 150kg man, 22°C in the living room is probably already too warm. My wife still walks around in 3 layers at 24°C ;-)
That means: Maybe your neighbor has "only" 20°C in the living room and is also satisfied with 20°C in the bathroom.

To your question: I air out my bedroom for 5 minutes after getting up. After that, it takes until bedtime for the temperature to reach 18.5°C and for the ERR to close the circuits. I have 2 circuits with 0.2l/min each in the bedroom.

Bedroom

Window in the bedroom always open or what?
Measuring the outside temperature wouldn't be very useful.