Comparison tests of various central controlled residential ventilation systems + additional questions

Thank you very much for the answers! : )

Unfortunately, the statistics above do not show what I wanted to know. They only compare different types of central controlled residential ventilation systems.

The developer guarantees us that his house cannot develop mold and my better half is in any case a diligent manual ventilator. We will probably build without a central controlled residential ventilation system. However, I want a decentralized solution in the bathroom and in the large living-dining-kitchen area, respectively. Why? In the bathroom an automatic system (1 core drilling for supply and exhaust air) that measures the humidity. And the other room combo is in the south and there I want to get cool air in at night during summer without having the windows tilted open (There two alternating fans from GetAir). What do you think about that?

Since I am not a construction technician, I can only report the advice from our BU. The wall construction is Ytong, monolithic, i.e., plastered and painted, without thermal insulation boards. Standard Energy Saving Ordinance. Without special KFW levels. His words. Those who ventilate really well don’t need anything. But who actually does that? You also go on vacation sometimes, and besides, we still build with water, and in new buildings, that moisture has to get out first. And we build tightly, which we want and have to do because of CO2 savings and to reduce energy costs. Therefore, he would always install some kind of forced ventilation. He offered us a controlled residential ventilation system from Zehnder. I believe for a 7.5 price increase. Or from Helios a decentralized system, which was much cheaper, only about 1000,- extra. Now you should know that our house is small, only 108 sqm living space, all on one level. The Helios solution seemed sufficient for two people and a cat. It consists of an exhaust fan in the bathroom wall, running continuously, switchable off by a light switch if desired. There is a humidity sensor in it, so after showering, if it’s humid in the bathroom, it increases the speed. In each room, the window or windows now have a slot with a control air module inside, a kind of forced supply air. The fan extracts air, fresh air whistles in through the windows. The result, compared to the house of our children, same wall construction, zero ventilation, is striking. There it quickly becomes stuffy, overheated, with odd air. In our house, it’s not drafty, but you still have the feeling that the air is good. I would recommend such a system for little money to anyone. I feel well advised by the BU. Karsten

I can confirm the thing with the exhaust pipes. In our case, a filter cap was placed directly over the valve of the exhaust pipes (on the inside). These are then cleaned regularly with the vacuum cleaner. Maybe it's because of the new building... but the filters always have quite a bit of stuff in them.

Per ventilation:

[*]Less headaches because no slowly deteriorating air enters
[*]No fear of mold (not only walls but also objects in the room can mold)
[*]Bedroom still smells good after getting up.
[*]Indirectly: no ugly solar panels on the roof
[*]No unpleasant temperature drop when ventilating.

Cons:

[*]Air becomes somewhat drier in winter.
[*]Electricity consumption (--> as I have learned thanks to forum members, this is currently significantly too high for us.)

I can confirm the thing with the exhaust pipes. In our case, a filter cap was directly placed over the valve of the exhaust pipes (on the inside). These are then regularly cleaned with the vacuum cleaner. Maybe it’s also because of the new building... but the filters always have quite a lot of stuff in them.

Per ventilation:

[*]Less headaches because no slowly deteriorating air enters
[*]No fear of mold (not only walls but also objects in the room can mold)
[*]Bedroom still smells good after getting up.
[*]Indirectly: no ugly solar panels on the roof
[*]No unpleasant temperature drop during ventilation.

Contra:

[*]Air becomes somewhat drier in winter.
[*]Electricity consumption (--> as I have learned thanks to the forum members, this is currently significantly too high in our case.)

Dry air should be able to be regulated/avoided by supplementing the controlled residential ventilation with an enthalpy exchanger.

The developer guarantees us that his house cannot get moldy and my better half is a diligent manual ventilator anyway.

Ah yes... he guarantees that his house cannot get moldy. Excuse me, how is that supposed to work? What he probably MEANS is that he is only liable under warranty as long as a mold damage is unlikely to occur.

And does your wife also get up every few hours at night to ventilate? Probably not... At night you sleep best, and that only works well if the CO2 level does not rise endlessly. Which only happens with sufficient ventilation.

So please be honest! With the airtightness of houses today (well, as long as you don’t destroy the airtightness by tilting windows), anything other than mechanical ventilation is just window dressing, whether it concerns mold or "just" bad air. Decentralized ventilation is possible, but with correct design for the necessary amounts (in new buildings) in a normal single-family house (150 sqm) it is most likely only marginally cheaper.

In any case, ALWAYS with ventilation, if at all possible!

We will probably build without a central controlled residential ventilation system.

Bad idea... better to do without frills in the bathroom and kitchen or something like that... I can only agree with the previous speakers.