ᐅ KFN House Without a Ventilation System – Experiences

wiltshire schrieb:

This is something special for us: We don’t have a bedroom, but a "multi-purpose room" that truly lives up to its name.

But that’s precisely why you should reconsider your answers when someone asks. You can’t assume others are like you and then keep your response brief like

wiltshire schrieb:

In our house, completed in 2019, a ventilation system would be a complete waste of money without any added value.

ypg schrieb:

But that’s exactly why you should reconsider your answers when someone asks.

The phrase “you should reconsider” sounds a bit like kindergarten teaching.
But okay: a mechanical ventilation system is a good investment in many houses, though by no means an essential feature.
The original poster’s question cannot be answered with a general statement due to the limited information provided. There are plenty of other examples besides my house.
Better?

Maybe you should just read the funding conditions of the KfW. I quote:

A ventilation concept must be created, specifying the required outdoor air volume flow and the solution for implementation, for example by applying DIN 1946‑6. The client is responsible for ensuring the implementation of ventilation measures.

Good luck achieving this without a controlled residential ventilation system. It doesn’t help to say you don’t need it because you live in an earth house with 300 cubic meters (10,600 cubic feet) of interior volume, or that it’s a waste of money for you.

DIN 1946-6 clearly states: independent of users, so it’s not sufficient to just open windows occasionally...

wiltshire schrieb:

There are plenty of other examples besides my house.

Which would also need to be explained

wiltshire schrieb:

Better?

Kindergarten-level behavior is never appropriate for adults. That includes debating terminology.

Rübe1 schrieb:

DIN 1946-6 clearly states: independent of user, so it’s not about occasionally opening the windows...

A window rebate ventilation system meets the requirements of DIN 1946-6 and can be used in the construction of a KfW 40 house. Mechanical ventilation is not the only solution.
This at least answers the first part of the original poster’s question: yes, it is possible without mechanical ventilation.
Perhaps someone living in a house with window rebate ventilation can share their experience.

wiltshire schrieb:

But OK: A mechanical ventilation system is a good investment in many houses, but it is by no means a mandatory feature.

Let’s define "many": 98% makes sense, 2% are exceptions with special building physics conditions or similar.

For a standard house with normal use, it is a "must".

wiltshire schrieb:

A window rebate ventilation meets the criteria of DIN 1946-6 and can be used in the construction of a KfW 40 house. Mechanical ventilation is not the only solution.

A window rebate ventilation IS a form of mechanical ventilation. Only manual ventilation is not mechanical ventilation. Window rebate ventilation and KfW 40 require considerable effort to implement properly. You cannot ventilate a standard KfW 40 house like that, otherwise it ceases to be a KfW 40 house.