The purpose of the funding is to create LIVING SPACE for MORE people.
At least that is not stated as a funding purpose in the guideline, it says:
The aim of this guideline is to stimulate investments in comprehensive measures to increase energy efficiency and the share of renewable energies in final energy consumption for heating and cooling in residential buildings in Germany, and to reduce CO2 emissions in the building sector in Germany. The construction and renovation of residential buildings that feature energetically optimized construction and technical systems and meet the requirements defined in the technical minimum standards of this guideline in terms of overall energy efficiency (reference: primary energy demand) and the energy efficiency of the building envelope (reference: transmission heat loss) to achieve an efficiency house standard, are supported. Coherence with CO2 pricing and efficient use of funds with regard to the CO2 savings achieved is taken into account. The funding guideline contributes to reducing greenhouse gas emissions in the building sector to 70 million tons of CO2 equivalents by 2030, thereby achieving both national and European energy and climate targets by 2030. Moreover, the funding guideline implements the 2019 decisions of the Climate Cabinet and the Climate Protection Program 2030. With this guideline, approximately 50,000 comprehensive measures per year (full renovations to or new construction of efficiency houses) for residential buildings are to be approved, with a gross investment volume of around 32 billion euros, thereby reducing greenhouse gas emissions by approximately 520,000 tons of CO2 annually. Your interpretation is certainly not wrong, but at least from those who designed this thing, it is not mentioned with a single word. *shrugs*
I can’t name a source, but we have a granny flat and it has its own ventilation system. The general contractor actually wanted to install only one system for both units at first, we didn’t want that, and our expert also said that’s not allowed. A tenant must be able to regulate the system themselves; it can’t be that a tenant has to accept the settings just the way the landlord wants it for themselves.
As far as I understand, there are several requirement catalogs that need to be considered here. On the one hand, of course, the KFW requirement on “What is a dwelling unit,” then also the KFW requirements for efficiency classes. Depending on the class, there are different points that must be complied with. And then naturally the state building codes and such. I mean, I’m no expert, but after reading the guideline and the Building Energy Act, there seem to be very, very many things that influence each other and create dependencies that then become mandatory, even though this is nowhere explicitly stated.