Base load air-water heat pump for 30% living area?

Good day,

I have searched but haven't really found anything on this, we have been with many different providers by now and always had a calculation done for an air-water heat pump with underfloor heating. Recently, one provider explained to us that the bathrooms and the hallway are not separately controllable with this company because the air-water heat pump must always have a certain base load, which should be about 30% of the living area, and this is not adjustable separately in the room. This means the bathrooms and the hallway are set once directly through the system and then always have the same temperature; if there is a higher heat demand in the bathroom, the towel radiator must be used. All other rooms have their own controller. Now my question is, is this correct or why does no one else do it this way or is it simply not communicated?

You don’t have to do it that way, but it’s clever and sounds like someone knows what they’re doing.

This means that the bathrooms and the hallway are set once directly via the system and then always have the same temperature

This actually applies nowadays to every new building and for the entire house. The heating is properly set (and correctly planned beforehand) and then that's it.
With underfloor heating, you cannot just "quickly" raise the temperature either way. That can take hours if necessary.
So yes, if you want to quickly have it warm in the bathroom for showering, you MUST use the (electric) towel heater. You can only plan the base temperature differently than, for example, in the bedroom.

Good to know, then I have to ask about that directly with any future candidates. I don't think it's a problem either, and of course underfloor heating takes a long time to reach a certain room temperature, I also don't want to keep adjusting anything all the time. I had just thought I would prefer the bathrooms to be warmer than the hallway, but I think it's fine as it is and with a towel radiator it gets warmer relatively quickly if you ever need it. Many thanks.

The bathroom is already warmer than the hallway, it's just that it cannot be turned off. Basically, you can do this with all rooms, but it is not compliant with the energy saving regulations and is therefore not offered.

Sounds strange what they are formulating there.

An air-to-water heat pump does not need a base load.

The modern devices all modulate, which means they adjust their output to the consumption.
In the worst case, they start short cycling when they can no longer get rid of the heat.

However, this rather suggests that the heating system is too large/incorrectly designed.

The bathroom is important insofar as it is usually the room that should be the warmest and at the same time offers the least heating surface.

Therefore, it is usually the reference room for the flow temperature.

Regulation is never done through individual room control if you want to do it well anyway.

A towel radiator is NOT an additional heater; the contribution is so small that you might as well place a candle.