ᐅ Base load of an air-to-water heat pump at 30% of the living area?

Hello,

I have searched but couldn’t find a clear answer. We have been to many different suppliers and have always had an air-to-water heat pump with underfloor heating calculated for us.

Recently, one supplier told us that the bathrooms and hallway cannot be controlled separately because the air-to-water heat pump always requires a certain base load, which should cover about 30% of the living area. This base load cannot be adjusted individually by room. This means that the bathrooms and hallway are set once for the entire system and then always maintain the same temperature. If more heat is needed in the bathroom, the towel radiator has to be used.

All other rooms have their own thermostat.

My question is: is this correct? 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.

Rampelzampel schrieb:

Does this mean the bathrooms and the hallway are set once via the system and then always maintain the same temperature?

Nowadays, this actually applies to almost every new build and the entire house. The heating system is properly configured (and planned in advance), and that’s it.
With underfloor heating, you can’t just “quickly” raise the temperature. It may take hours.
So yes, if you want the bathroom to be warm quickly for a shower, you HAVE to use the (electric) towel radiator. You can only plan a different base temperature in areas like the bathroom compared to, for example, the bedroom.

Good to know, I’ll make sure to ask about that directly with any potential candidates in the future. I don’t see it as a problem, and of course, underfloor heating takes time to reach a certain room temperature. I also don’t want to keep adjusting it all the time. I just thought I’d prefer the bathrooms to be warmer than the hallway, but I think it works fine as it is. Plus, with the towel radiator, it heats up relatively quickly when you do need it. Many thanks.

The bathroom is already warmer than the hallway; the issue is simply that it cannot be turned off. Essentially, this approach could be applied to all rooms, but it would not comply with energy efficiency regulations and is therefore not offered.

What they are saying sounds strange.

An air-to-water heat pump doesn’t need a base load.

All modern units modulate, meaning they adjust their output to match the demand.
In the worst case, they start short cycling when they can’t get rid of the heat.

This usually indicates that the heating system was sized too large or designed incorrectly.

The bathroom is important because it is usually the warmest room but at the same time has the least available heating surface.

Therefore, it is often the reference room for setting the flow temperature.

If you want to regulate properly, you never rely solely on individual room control.

A towel radiator is NOT an additional heat source; its contribution is so minimal that you might as well just light a candle.