KfW 70 without ventilation system

Congratulations Lacos! You fell for a pure scare story!
In today's controlled residential ventilation systems, filters are used. Nothing gets dirty anymore...
The TV report you linked is complete nonsense...


With my controlled residential ventilation, the manure odor stays outside
That doesn't work with window ventilation

Good, I can understand that there is a filter in front of the fresh air. But not in the exhaust air, right? So theoretically, something should accumulate quite well in the exhaust air ducts over time.

But filter bags can also be used in the exhaust air plate valves.

Yep, the exhaust air must be equipped with filters so the system stays clean

So, we are currently building KfW 70 standard, brick construction, diffusion-open and also completely without a ventilation system. The disadvantages of such a system are just too big for us. At first, I thought I wouldn't build without it because I am allergic, but after some inquiries, research, and trying it out, we quickly moved away from the topic. The biggest disadvantages from our point of view:

- the low humidity, sometimes below 25% in winter, is extremely harmful to health, respiratory diseases are inevitable, people's countermeasures: hanging wet carpets, placing humidifiers in the rooms, or turning off the system – but then you question the point of the system...
- The thing has to run continuously; if not, there is a risk of water deposits which can form bacteria and lead to contamination of the entire rooms.
- the ongoing maintenance costs
- the constant dust exposure, because air is always moving. According to studies, sometimes there is more fine dust exposure inside houses than on busy streets in big cities...
- possible odor formation in the pipes (after years), which spreads into all rooms, as well as possible noise pollution from the system, e.g., in the bedroom (many are disturbed by the humming/buzzing, and yes, it is usually below the noise pollution limit for bedrooms (I think 30db?), but still audible – it would bother me)

For me, currently just a marketing gimmick to take money from people’s pockets and to somehow meet the desired energy standards. My opinion: in a normally built new building, nothing molds, it takes quite a lot for that to happen, just looking at the surface temperatures, it’s almost impossible. From almost all construction companies, we always heard that we absolutely need it; nowadays, you don’t build without it. When asked about disadvantages, the only answer was, "there are no disadvantages." That’s precisely why we questioned the systems. It is really not easy to get independent advice. Energetically, it’s a zero-sum game, climatically, biologically a disaster (we like to know that it’s snowing outside or summer!).

Hello,

The biggest disadvantages from our point of view:

- the low humidity, sometimes below 25% in winter, is extremely harmful to health, respiratory diseases are inevitable, people's countermeasures: hanging wet carpets, placing humidifiers in the rooms, or turning the system off – only then you wonder about the purpose of the system...
- The unit must always run, if not, there is a risk of water deposits which can form bacteria and lead to contamination of the entire rooms.
- the ongoing maintenance costs
- the constant dust burden, as air is always in motion. According to studies, sometimes more fine dust pollution inside the house than in heavily trafficked streets in big cities...
- possible odor formation in the pipes (after years), which is carried into all rooms, just like the possible noise pollution caused by the system, e.g. in the bedroom (there are many who are disturbed by the humming/buzzing, and yes it is usually below the limit for noise disturbance in the bedroom (I think 30db?), but still audible – it would bother me)

My partner argues like this too; he is not only a businessman but also a trained gas and heating installer.

Rhenish greetings