New construction KFW 70 house and your opinion on our project

Sure, I deliberately used the word verquer because your answer, just like your sentence sounds, only confused a bit when reading and is not directly wrong.

Yes, actually everything has already been said on the topic...building without controlled residential ventilation...means in reverse for me: someone is always at home and can heat and ventilate...

In my opinion, the working population cannot maintain the ventilation intervals...at least we cannot and neither can our friends/relatives.

And if there is no mold yet...it will come eventually...people nowadays live in a plastic bag...the moisture simply cannot escape easily...unless one can maintain the heating/ventilation intervals (see above), or the house was built so poorly that it drafts at every corner...

Thank you very much for the many responses from you. I have now spoken with the heating company and they are now offering me a system from Viessmann. I believe Vitovent 300.

But now to my actual question. How did you decide at which points to use more insulation? The question has surely been answered by everyone for themselves in their own construction. In the second post, you can see the current facts.

Best regards

From my heating load calculation for our kitchen:
Floor slab: 28.52 m² * 0.17 W/m²K * 20 K = 96 W (assumed 0°C outdoor temperature)
Exterior wall: 19.84 m² * 0.186 W/m²K * 32 K = 118 W
Window: 10.48 m² * 0.78 W/ m²K * 32 K = 262 W
Thermal bridges: 58.84 * 0.05 W / m²K * 32K = 95 W
Ventilation losses: 90 W (600 W total / 190 m² living area * 28.5 m² room area)
________
661 W

Rafters /top floor ceiling are at 0.156 W/m²K.

Your HT is still better than mine (0.234 vs. 0.246) - but that is probably due to your window area of 18.5 m².
My primary energy demand is 31 kWh below yours - but that is only because of the generator. We calculate monthly costs for hot water and heating of about €55 (11,400 kWh and an annual performance factor of 4.5).

What would I take away? You will have low heating costs - whether more insulation makes sense for your building is unclear - what might be worthwhile are more windows.
What heating demand do you have listed for yourselves? Then you can calculate what you would now pay and what you would have to do to pay less. Relatively easy to realize is certainly better roof insulation - of course depends on the planned rafter thickness.

Hello and thanks for your reply. I do not have any information on the heating energy demand. The only documents from the energy consultant are already attached in the second post. The heating energy demand is then consequently lower than my annual primary energy demand, or have I misunderstood something? Why would more windows be sensible? That would worsen the HT value, wouldn’t it? In the calculation of the window area, the architect of course took the location/orientation of the building into account accordingly.

Because you have 18 sqm of windows with 240 sqm of usable space. How much of that is unoccupied?