Decentralized exhaust system/ventilation system WITHOUT heat recovery in KFW 40 new building

What does the KfW application/proof say? What does the ventilation concept according to DIN say?

What does the energy consultant, who has to do the BnD, say? And finally: really a property developer?

Great, it's like having windows open all the time. It was popular in the 1940s. No (central or decentralized) ventilation system in new buildings is roughly like buying a new tube TV. You can do it - but you don't want to, because there are only disadvantages. In new buildings, you do: 1. central ventilation system 2. decentralized ventilation system if money is tight 3. window rebate ventilation if you actually can't afford to build the house but do it anyway (no offense)

Hi So I wouldn’t put up with a forced ventilation. If you want to keep the heat out or the stink because the neighbor is grilling, you don’t stand a chance. Controlled ventilation sure, if not possible then hand ventilation. PS forced ventilation via window gap ventilator you can retrofit anytime for little money if necessary - but it’s still crap... GD

Hi I would not put up with a forced ventilation like that. If you want to keep the heat outside or the stink because the neighbor is grilling, you have no chance. Controlled ventilation sure, if not possible then hand ventilation. PS You can retrofit forced ventilation via window rebate ventilators at any time for little money if necessary - but it still remains rubbish... GD

PS: as a landlord I would install forced ventilation.

Now we have the information that we could also do without the ventilation system and save €1,300.

P.S. That is the savings for two decentralized units. So actually no credit at all for a ventilation system for the entire house. I would also be interested in the calculation to achieve KfW. After all, KfW 40 (!!!), where building with window rebate vents really messes up the entire calculation. Do you spend such a fortune on an extremely high-quality house that in the end it comes down to €1,300? There are dozens of things I could do without – a young used property without a ventilation system is like a new car with a big scratch on the market. Also keep in mind that you want to sell a property again someday. Or would you still buy single glazing today?