KfW loan in 2017 for a house under the 2016 Energy Saving Ordinance

The house that was offered to us does not have a ventilation system. Correct. Is that bad? Are there serious disadvantages?

It has disadvantages in that you yourself have to walk through your house up to three times a day and ventilate by opening the windows briefly to ensure air exchange and to remove moisture (sweat, water vapor) from the house.

Last year there was still Kfw 70. The thing with ventilation is also greatly exaggerated. Normal air exchange must also be ensured without constant shock ventilation. However, after showering, cooking, etc. ventilation should be done.

You had enough time to inform yourself in the meantime, right? I mean, you haven't just been here in the forum since yesterday and there are plenty of posts about KFW, heat pumps, etc...

If you want to build according to the Energy Saving Ordinance, you can only fall back on program 124 as well as, under certain conditions, the funding by the municipality ([kommunale, soziale Wohnraumförderung]), but I guess we've already discussed that topic as well.

you do realize that you are talking complete nonsense, right?

It is not nonsense, but a reasoned position of mine. In September last year we commissioned the house, calculated back and forth with the general contractor whether a KFW 55 standard is economically viable, repayment bonus, interest, etc. For us, no. That is the result. And the house would not have gotten different walls, different windows, or different roof tiles in kfw 55, only different and more expensive building services engineering.

And the house would not have received different walls, windows, or roof tiles etc. in KFW 55, only different and more expensive building services.

Then it is strange that KFW 55 was unprofitable for you, because you had already factored in the essential additional expense from the Energy Saving Ordinance to KFW 55 (walls/windows/insulation).

The statement that only technology is necessary from the Energy Saving Ordinance to KFW 55 is nonsense. That is simply false.

My facts: A rectangular bungalow, ground slab 13.5 by 10. No L, no U. Few window areas facing north, floor-to-ceiling windows only facing southwest, no basement, Ytong monolithic plastered, condensing gas heating plus solar thermal, underfloor heating, triple glazed, Rehau profiles, easily meets the Energy Saving Ordinance Standard 2016, to reach KfW 55, an air heat pump heating system and an exhaust air system for heat recovery would be necessary, solar thermal could have been omitted. The repayment subsidy does not offset the additional cost of the technology. The KfW interest rate was almost identical to that offered by the bank anyway, according to the general contractor the energy costs will not decrease monetarily, because although the air heat pump does not use gas, electricity consumption increases enormously. Only the one-time gas connection costs of 1500 at the gas supplier would be a positive.
Uncertain, however, he said, is the susceptibility to faults of the control technology in the pump systems, while solar thermal and condensing gas technology are well-tested, durable and not very prone to faults. That’s how I was advised.