Energy Saving Ordinance 2016 or KFW 55 for bungalow with air-water heat pump & controlled residential ventilation, optional photovoltaic

Energy Saving Ordinance applies, you will never recoup €15,000 with heating,...

What do you want to build the house from, did I miss that? Ytong, aerated concrete?

Aerated concrete is at least according to the offer

: I didn't quickly find it from Vaillant, but the Nibe F730 has exactly this exhaust air heat pump, why should it be worse than external air? The system is the same

Basically, the planner has to point out the issue of depreciation, because in about 1-2 years the Passive House standard will apply in the Energy Saving Ordinance.

Basically, a KfW55 house should therefore be recommended, as it should keep the depreciation within limits before the house is occupied.

The only question is how the house is verified, i.e. how good the building envelope really is. That means without a high primary energy factor like with electricity or even with photovoltaics.

Easily seen via the room heating load according to DIN EN 12831.
Note, not the building heating load. The sum of the room heating loads is usually higher than the building heating load. In the case of a KfW55, up to one third or more.

The exhaust air of the house alone is not sufficient to operate the heat pump. It must then either be reheated electrically or the heat pump can additionally tap the outside air. Whether the latter is the case here, I do not know. The latter increases complexity/acquisition and depreciation costs, and the purely electric heating simply causes costs.

There are few reasons that argue in favor of such a heating system. However, general contractors apparently like to use it.

With a normal controlled residential ventilation, the heat in the exhaust air is also not lost.

KFW 55 as a stamp is rather uninteresting. With an air-water heat pump, the heating load would be more important to me and I would limit it to 5kw. That is then certainly also a kfw 55 house.