Combination of ventilation system and solar system for domestic water?

How do towel radiators actually work in this context? With +/- 30° supply temperature and the moderate surface area, I suppose they heat very little?

Correct, in this case more like a towel holder. The output share for covering the room heating load is very limited, especially when covered with a towel. There is something comparable with underfloor heating => not or only limited active heating surfaces. Typical, for example, in bathrooms or kitchens. The planner must take this into account when sizing the heating surfaces.

regards

How do towel radiators actually work in this context? With about +/- 30° flow temperature and the moderate surface area, I guess they don't heat much?

Hello Musketier

with us purely electric.
Not connected to the heating system.

The advantage is that you can turn on the radiator before the kids bathe to "quickly" heat the room. Or when showering, to preheat the towels.
Running costs? We’ll see. It’s one of the points I optimized for comfort - not for cost

Regards
Micha

The question is whether one can still easily achieve KfW 70 without a solar thermal system.

Hello Watislav

yes, you can.
As an example (not to be generalized):
I had to increase the roof insulation from 20 cm to 24 cm in order to comply with KfW 70 and the Renewable Energy Heat Act.
For that, I saved myself the solar thermal system and now have the entire south roof area free for photovoltaics.

I do not yet have the final invoice from my builder, but everyone can probably imagine that it is an extreme cost saving to install 4 cm more material (assembly work/time is the same) instead of a solar thermal system. (including costs for the loan/financing of this amount).

So it's worth at least having the 15% rule checked. It should often bring an extreme advantage!

Regards
Micha

How many thousand euros can be saved by giving up on a [Solarthermieanlage] and having to insulate more instead? Just roughly. Actually, we do want to use solar energy, and if it's "only" 2-3 thousand euros, then giving it up is not an option for us.

If you want a solar thermal system for ideological reasons, then just take it. Whether you save money through insulation instead of a solar thermal system or have to spend more depends on your specific house project and can only be answered by your planner/provider.

Hello,

... but everyone can probably imagine that it is an extreme cost saving to install 4 cm more material (assembly work / time is the same) instead of a solar thermal system. (incl. costs for the loan / financing of this amount).

If I were you, I wouldn’t be so hasty; I’m already looking forward to your post on the topic when the final invoice is available

Rhenish greetings