Extractor hood with exhaust air at KfW55

We also plan to operate controlled residential ventilation, exhaust air, and a fireplace. The chimney sweep and energy consultant were consulted, and here is the answer from the energy consultant.

„...from the KfW's perspective, the range hood can be disregarded. Since it is a small, localized thermal bridge, it does not need to be included in the energy balance.
And regarding the blower door test, the outdoor opening of the system is included in the balance but should not predominantly influence it, as the outdoor opening is relatively small.
A special external flap is not required.“

The exhaust air is to be routed outside through a DN150 pipe in the floor slab.

not because it doesn’t work, but in connection with a controlled residential ventilation system, it is very complex and therefore expensive.
For example, an automatic window opening must be implemented so that a window opens by itself as soon as the exhaust air turns on.

That was also explained to us that way. Especially if a fireplace is supposed to be added later, like in our case..

Then you additionally need a negative pressure (or air pressure or something similar) monitor that controls the whole thing, so that not too much air escapes and not too little fresh air comes in. Additionally, window contact.

That was all too complicated for us :)

We are now doing recirculation, central controlled residential ventilation, and gas fireplace.

We were also explained it like that. Especially if a fireplace is added, like in our case..

Then you additionally need a negative pressure (or air pressure or something similar) monitor that controls the whole thing, so that not too much air escapes and too little fresh air comes in. Additionally, a window contact.

That was all too complicated for us :)

We are now doing recirculation, centralized controlled residential ventilation, and a gas fireplace.

Well.... too much air escaping is basically only a problem with a fireplace since it affects the chimney.
If the air became so thin without a fireplace that I had breathing problems, I would turn off the exhaust beforehand ;)

Or are there problems with negative pressure on the controlled residential ventilation side?

Well.... too much air escaping is basically only a problem with a chimney because it affects the flue. If there is no chimney and the air gets so thin that I have breathing problems, I would turn off the exhaust air beforehand ;) Or are there problems with negative pressure on the side of the controlled residential ventilation?

Have a look here, that's where all the info came from: