Door gap Controlled residential ventilation Ventilation gap for air exchange

This is how it looks from above:

Maybe you can install a bypass opening in a part of the wall where it cannot be seen. There are supposed to be such boxes for installation...

Hi, thanks!

Well, we don't really want to recess anything into the wall, that doesn't really look good, but exactly like the gap under the doors. Retrofitting the frames is also out of the question.

So I think we'll create a bit more space under the doors, it's not like there's no room at all.

But the question I still keep asking myself is: What happens if the calculated values are not adhered to. Sure, the air exchange takes longer, but it still happens. There are also people who don't run their controlled residential ventilation regularly at all. That basically comes down to the same thing. Or if the doors are open, the calculated system is irrelevant anyway. There are only two of us and we're not home all day anyway, so in my view, it doesn't matter.

One could maybe argue here again that the values are calculated and should be adhered to, but maybe it's a bit like using a sledgehammer to crack a nut.

There are also people who don't even run their controlled residential ventilation regularly. That ends up being the same anyway. Or if the doors are open, the calculated system is pointless anyway. We are only two here and not home all day anyway, so in my opinion it doesn't matter.

One could maybe argue again that the values are calculated and should be adhered to, but maybe it's also a case of using a sledgehammer to crack a nut.

I'm just wondering why you install a system for air exchange and then want to "limit" the air exchange again? Maybe a decentralized system - or none at all - would have been better for you.

You could have just given the money to me too

Well, it’s not as if the function is completely restricted when the gap falls slightly below the target dimension. The pressure differential becomes somewhat larger due to higher flow losses. Ideally, this causes a slight draft at the narrow point (which hardly anyone will be bothered by, since who stays constantly in front of the door). Audible noise could occur, but for that, quite a bit of air would have to whistle through. My biggest concern would be that due to the pressure differential, air flows uncontrollably through the smallest cracks in the masonry, at the windows, etc., instead of through the door gap...

Hello PhoenixDH,

Quote: "One could perhaps argue here again that the values are calculated and must be adhered to, but maybe it is also like using a sledgehammer to crack a nut."

Why should that be the case? The controlled residential ventilation is designed according to DIN 1946-6. For this purpose, an air volume plan is created. But not arbitrarily and at one's own discretion, rather the air volumes are calculated. And these calculated air volumes must pass through the overflow opening/door gap at the specified pressure loss. Accordingly, this must also be calculated.
If the gap is smaller, the system cannot operate as intended. This means possibly
- the planned air volumes are not achieved
- the pressure loss increases, causing the power consumption to rise
- the infiltration air volume flow increases, meaning more heating energy consumption
- the allowable pressure loss is exceeded, which in turn disrupts the safe operation of a chimney
etc.

Best regards
miraculum