Is a gas condensing boiler without solar thermal sufficient for KfW-70?

Dear forum community,
I have already posted something about heat pumps etc. and read a lot of interesting things. We want to build (solid) and have signed the contract with our developer, the plans are drawn up and the application for the KfW loan is also prepared (the loan has already been granted, but I still need the proof).

The architect calculated an annual primary energy demand of 36.2 kWh/(m²a).
We want to heat and provide hot water with a heat pump (IWS, brine-water, including controlled ventilation with heat recovery up to 90 (?) percent).
The windows are double-glazed, the exterior walls are approximately 44 cm thick in total (Poroton, insulation, facing bricks).

The architect also included a solar thermal system for hot water preparation. But we do not want that at all – and he said: Then KfW 70 will not be reached! :confused: :(

He said the heat pump consumes electricity and that is bad.
If we installed a gas condensing boiler (but no solar thermal) KfW 70 would be reached.
I had rather expected that with the heat pump, ventilation, heat recovery and the general insulation we would at least reach KfW 70, possibly even KfW 55.

I am already quite frustrated about this...
:(

I should perhaps mention: We have electric roller shutters and are considering possibly installing a photovoltaic system on the roof (however, this is not yet certain).

I would doubt just as much as you. We achieve KFW 70 by installing a heat pump instead of a gas condensing boiler and solar. Why should it be the other way around for you? The only thing I noticed in your entire list are the double-glazed windows. You invest a lot of money in the building envelope, heating, and controlled residential ventilation with heat recovery, and then save on the windows?

Hello,

...and have signed the contract with our developer, ...

A general contractor (GU/GÜ), not a developer (BT)! The legal differences should actually be known!

....The architect also included a solar thermal system for hot water preparation. But we don’t want that - and he said: Then KfW 70 won’t be reached! :confused: :(

With an installed ground-source heat pump, it’s usually not qp´´ but rather Ht´ that is the problem. How this is to be solved or can be solved with a solar thermal system is probably only known by this architect! ;-) I would get rid of such a dud!

....He said the heat pump consumes electricity and that this is bad.

There is basically no such thing as free of charge! ;-)

...If we installed a gas condensing boiler (but no solar thermal) KfW 70 would be reached.

How should that work without additional thermal insulation (15% rule) EEWG? ;-) Does he actually know what he’s talking about?

....I had rather expected that with heat pump, ventilation, heat recovery and the general insulation we would reach at least KfW 70, possibly even KfW 55.

With the heat pump as installed heat generator, it is usually not qp´´ but rather Ht´ that is the problem to reach, e.g., KfW 55. For KfW 70 usually completely unproblematic!

....I’m already quite frustrated about this...

Maybe better (beforehand) ask an expert ;-)

Best regards

The architect has been working for our general contractor for many years, and he is very satisfied with him.

That may be an advantage for the two of them, but is that good for you...?

So we are currently working on a KfW 70 house as well. We have no solar, no photovoltaics. But an air-to-water heat pump and triple-glazed windows. Unfortunately, I don't know the name of the stone right now. But it is not Ytong. The insulation will then be calculated so that we achieve KfW 70. Our architect said that triple glazing is already standard today. And you have to be careful that the insulation thickness matches the windows so that they don’t sweat.