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

But I thought it shouldn't be completely closed off at all?

yes, you are right about that, but I also have my bedroom completely closed... I don't want any temperature there...

yes, you are right about that, but I have also completely closed my bedroom... I don't want any temperature there...

I myself have a small minimum flow even in the utility room where the heating, washing machine, and freezer are located, although it wouldn't be necessary. The hydraulics of Chewbacca123 are somewhat borderline; every heating circuit that is even slightly open is needed.

You should briefly explain what that achieves? That way you reduce the flow of others, don’t you?

You prevent the unheated room from drawing heat from the others. Therefore, maintain a minimum flow to supply the energy that the room loses to the outside directly into the room via the underfloor heating. But, for example, in the bedroom, not more than that to avoid heating it up. The goal is to minimize the heat flow between the rooms. To stay with Chewbacca’s house example: If the hallway and bedroom are not heated, heat flows from the bathroom through the hallway to the living room, and the bathroom gets even colder. This means turning up the heating curve, resulting in higher heating costs without effectively having more heat in the rooms. You can do that, but why waste money. Therefore, ultimately save money through the thermal balancing of the underfloor heating with the lowest possible heating curve. In the case of the undersized bathroom heating surface, I would possibly even use the hallway to get heat into the bathroom. So do not keep the hallway temperature too low and keep the door to the bathroom open.

I would possibly even use the hallway to get heat into the bathroom in the case of an undersized bathroom heating surface. So, don't keep the hallway temperature too low and keep the door to the bathroom open.

But that only works if, with closed doors, the bathroom temperature is less than the hallway temperature. That also means that the hallway temperature would actually have to be significantly above your own desired temperature and above the desired temperature of the other rooms. However, by heating through the hallway, you end up heating all other rooms as well and probably have higher temperatures in all rooms than desired. This, however, results in higher losses at the exterior walls again. Then the question arises whether this is more sensible than shifting the temperature curve up by 1-2° to reach the desired temperature in the bathroom without heating all rooms more than absolutely necessary. On the other hand, if you have to significantly raise the supply temperature, your variant of additional heating via the hallway is likely better.

The door to the bathroom must remain open, that is the requirement, door to the bedroom closed. She cannot reach 21°C in the bathroom, significantly more in the hallway. But I would first look where she ends up after the balance with the bathroom, maybe there is still something possible. There are still flow reserves in the bedroom, utility room, and hallway. Only when the balance is complete can a decision be made about what to do with the bathroom.