KfW 55 - Ventilation system yes/no? - Experiences

That’s not quite true either. Almost everyone who has a ventilation system says they are very satisfied and would do it again.
Only many who don’t have one still speak badly of it.

I have a central ventilation system and would not do it again. Firstly, because it makes noise (though very quiet). Secondly, because in my opinion it is simply unnecessary. In the first 5 years after the new build it definitely helped to get rid of moisture (but that can also be solved by proper ventilation). After that, we only turned it on in winter because the windows are often open anyway in summer. By now we don’t turn it on at all anymore because the indoor air is so dry that it becomes unpleasant. We also ventilated regularly even with the ventilation system.

P.S.: The maintenance effort for the ventilation system is minimal and almost negligible. The power consumption is as well.

Do you have an enthalpy heat exchanger, that is, moisture recovery?

We had the same problem in our rental apartment with controlled residential ventilation without heat recovery, all the plants died too. Now with heat recovery, they are doing great.

The ventilation system is a comfortable method to regulate the indoor climate. We decided against it because, like , we prefer to live with the windows open.

As far as humidity is concerned, everything is quite stable and within a pleasant range even without special technology. Here are the data from the past week.

how does the CO2 measurement work with closed windows?

Thank you for the reminder. I will have a look for the measuring device in a moment, it is still in the garden construction trailer.

I have a central ventilation system and wouldn’t do it again. First, because it makes noise (albeit very quiet). Second, because in my opinion it’s simply unnecessary. In the first 5 years after the new build, it definitely helped to get the moisture out (but that can also be solved by proper ventilation). After that, we only turned it on in winter because in summer the windows are often open anyway. By now we don’t turn it on at all because the indoor air is so dry that it becomes unpleasant. We also regularly ventilated with the ventilation system.

P.S.: The maintenance effort for the ventilation system is minimal and almost negligible. The power consumption as well.

For heaven’s sake. This is one of the big mistakes. A ventilation system must always run, it must never be turned off. Otherwise, over time the entire system will get dirty and you’ll breed germs.

1. You are allowed to open windows with a ventilation system. In summer, we do this very often. 2. An enthalpy heat exchanger solves your problem with dry air. 3. If you hear a central system, then it was planned incorrectly. Then never get a decentralized system; that is much louder. 4. A ventilation system is less about moisture or mold, more about air quality. Google CO2 levels and inform yourself. You would have to ventilate manually every 2-3 hours, which isn’t possible if you’re sleeping at night. And during the day it can be quite annoying as well.

But interesting how a useful technology can be made completely useless through planning errors.