Retrofitting split air conditioning in a kfw55 house

Hello everyone,

we live in a flat in a 2-year-old kfW 55 multi-family house. For the warm summers, we would like to install a split air conditioner in the bedroom just for cooling.

I have already read various things about this and how it might negatively affect the calculation and possibly the kfw funding.

Depending on where you read, you find the following versions: a) not at all, since it has nothing to do with the originally planned concept and is not relevant for the heating of the house, but only a comfort issue like a plug-in fan heater

b) only regarding the effects of the core drilling through the exterior wall

c) related to operation with cooling/heating, although it is not clear to me which consumption values should be used as a basis

Can you help me here? I also can't find clear information on this from kfw.

Can you help me here? I also can't find clear information from the KfW.

The KfW clearly states in its conditions that changes to the house that would invalidate the requested funding (i.e. airtightness no longer given, energy efficiency no longer KfW 55 or similar) within the first 10 years after funding will result in you having to repay the funding. Whether and how the air conditioning negatively affects your house is something a planner and/or energy consultant can tell you. And now comes my personal answer: Do it and don’t ask too many questions.

And now comes my personal answer: Do it and don’t ask too many questions.

Definitely no core drilling! The exterior wall is common property: it must be clarified in advance whether you are allowed to make a hole in the facade or attach something there. After all, it is not a single-family house where you can do whatever you want.

Core drilling through the exterior wall

What does the owners' association say about the project?

The exterior wall is common property: it would need to be clarified in advance whether you are allowed to make a hole in the facade or attach something there.

I assume this question has been answered. Drilling is the lesser issue (20mm), the appearance on the outside is usually the dealbreaker.

Thank you for the answers. Consent from the WEG regarding the appearance etc. is of course given. Just "simply doing it" is too risky for me, as then, of course, the other owners would also be affected regarding their funding.

Exactly, the KfW says that no changes to the house need to be carried out or otherwise approved within 10 years. But nowhere is anything more concrete described, such as whether/how the split air conditioner is taken into account in a calculation. Of course, I can commission the planner to take a look and possibly recalculate something. But I find it hard to believe that I am the first with this topic.

Therefore, I would be interested in how this turned out for others who went through the planner or what the feedback on this was.