Bafa funding for heat pumps will be discontinued as of 31.12.2020.

Regarding 3) ask if you have paid the heat pump costs from your 153. There is % less funding. If there are multiple individual loans, you deny that because you have "explicitly" paid the heat pump costs from the house bank loan. This is more relevant if you only have the KfW loan.

I was actually able to speak with someone at BAFA earlier. If I confirm on the application that the funded measure was not paid for with KfW funds, that is sufficient for them initially. Only if something seems suspicious to them during the review will they inquire more thoroughly. In my case, this can be credibly explained, as I first used the KfW loan to pay the initial installments over a year ago, then came the loan from the house bank, and now only equity remains.

Has anyone already realized and obtained approval/funding for this?

Heat pump brand X with ventilation system brand Y and they communicate with each other.
If yes, how?

I had previously posted a few threads, more like a How To from Novelan/ventilation (any brand) and I would be interested to know if there are any alternatives. WITHOUT KNX please.

Has anyone already realized and had it approved/supported? Heat pump brand X with ventilation system brand Y and they communicate with each other. If so, how? I had started a few threads more like a How To from Novelan/ventilation (any) and I would be interested to know if there are any alternatives. WITHOUT KNX please.

… with the proposal I confronted various heating engineers and consistently only got shoulder shrugs. If there is nothing from the manufacturer, they stay away from it. That is why I have now had a Stiebel Eltron combi unit installed

Zehnder offers a so-called "Option Box" with a 10V input, which just needs to be switched somehow through your smart home system (together with the heat pump). This is supposed to make it eligible for funding. They, I believe, built it especially for this purpose (the funding eligibility); they themselves are less convinced that it really provides an advantage.

It doesn't have to be KNX. You can connect the two with any Smart Home system or middleware like iobroker, Openhab, etc. I believe I read that this was also done successfully.