Gas and Solar Thermal - Questions about the Offer

We have gas WITHOUT solar and with the anyway and anyway desired controlled residential ventilation with heat recovery. And thus no additional costs for solar thermal energy. Also no problems with scalding, maintenance of a useless system, overheating in summer, etc...

That is a sensible, but unfortunately far too rare combination. Often gas with solar is offered off the shelf. More or less pre-calculated. Very unfortunate.

Karsten, we mostly share the same opinion. The rest are nuances and partly coffee grounds reading. I have also now chosen gas in the existing building for different reasons.

Can anyone say something about the following points?

Are circulation pipes necessary? ("Die Trinkwarmwasserversorgung des Hauses erfolgt zentral ohne Zirkulationsleitungen")

Which screed for underfloor heating? ("Nach Wahl des Auftragnehmers wird ein Zement- oder Anhydritestrich eingebaut.")

We have gas WITHOUT solar and with the controlled residential ventilation with heat recovery that was desired anyway and anyhow. And therefore no additional costs for solar thermal energy. Also no problems with scalding, maintenance of a useless system, overheating in summer, etc...

Hello Grym,
then it won’t work with KFW 55 for me?

2.) One of the following 6 system concepts must be implemented for the technical equipment. The location of the heat generator or the heat transfer station must be within the thermal building envelope and a central domestic hot water preparation must be present. Domestic hot water circulation is allowed.

[*]Condensing boiler, solar domestic hot water preparation (standard values according to DIN V 4701-10), central ventilation system with heat recovery (heat provision efficiency > 80 %)
[*]District heating with certified primary energy factor fp ≤ 0.7, central ventilation system with heat recovery (heat provision efficiency > 80 %)
[*]Central biomass heating system based on wood pellets, wood chips or firewood, central exhaust system
[*]Brine-water heat pump with surface heating system for heat delivery, central exhaust system
[*]Water-water heat pump with surface heating system for heat delivery, central exhaust system
[*]Air-water heat pump with surface heating system for heat delivery, central ventilation system with heat recovery (heat provision efficiency > 80 %)

Screed n.a. Circulation pipe: How far is the bathroom from the utility room. If close, skip it. If farther away, the water runs cold for 60 seconds and then becomes warm.

It definitely depends on the floor plan. I would always plan in such a way that you can do without circulation. Because it is also an energy guzzler for you

Circulation is a comfort issue. I wouldn’t want to do without it. Even if it’s only about 5-10 seconds. Most of the time it’s significantly more.

Gas, no solar, controlled residential ventilation, anhydrite screed, circulation, no KFW... that would be my choice.