Is controlled residential ventilation with a thermal wall necessary?

We have an offer for house construction from Bien-Zenker. They use a thermal wall with a total thickness of 336mm, 200mm wooden frame structure, 300mm thermal insulation. Thermal transmittance coefficient: U= 0.142 W/m2K.

My husband is afraid that because of the wood in the wall, we will also need controlled residential ventilation to prevent mold. As heating, there is an air/water heat pump. However, we definitely do not want controlled residential ventilation. But if it is required for this wall, we would choose a different provider.

What do you think?

Thank you very much and Merry Christmas!

Hello Anni,

My husband is afraid that because of the wood in the wall we will also need controlled residential ventilation to prevent mold. The heating system is an air/water heat pump. But we definitely do not want a controlled residential ventilation. However, if it is required for this wall, we would choose another provider.

I have been working in this business for a long time now, and you can trust me when I say that I initially had a very hard time with "holes" in the wall.

Today, houses from reputable providers – regardless of the system and wall thickness – are built so airtight that it would be almost negligent to forgo controlled ventilation. Even if one of you is at home all day, from all experience the occasional airing is not enough to remove the water content present in the new build for at least the first six months. You can easily imagine what can happen when both of you are away at work during the day...

There are excellent suppliers of ventilation systems on the German market, equipped with all necessary certifications and guarantees; the cost of the system is well invested. As for me – although I build monolithically – I will no longer sell a house without a ventilation system; unless the customer releases me in such a way that I have informed them about the risks. The current results of the blower door tests in our houses have made me rethink.

Merry Christmas

Hello,

... However, we definitely do not want a controlled residential ventilation system. If it is necessary for this wall, we would choose another provider...

A controlled residential ventilation system offers more comfort but is neither mandatory nor always absolutely necessary! The business based on fear of mold works quite well and generates additional revenue for providers. To avoid all eventualities, it has become common practice to have the customer sign a corresponding risk document. This alone causes the controlled residential ventilation system to become part of the contract for many customers.
One should always consider the individual case. Besides the wall construction, location and user behavior play a significant role. For this purpose, I have developed a form whose evaluation determines the necessity of a controlled residential ventilation system. Although I plan heating and ventilation systems and appreciate every order, I only plan the latter where absolutely necessary, unless they are requested for comfort reasons! Especially with timber frame construction, the construction-related moisture ingress is significantly lower compared to "solid construction," so there is relief here as well.

Best regards

@ Euro: Thank you very much.

For health reasons, I am not allowed to install a controlled residential ventilation system. I have serious eye problems, so my ophthalmologist strongly advised against it.

Therefore, we are looking for a construction method that works without controlled residential ventilation and, with normal ventilation behavior (several times daily airing as one has been used to since childhood), also prevents mold.

Hello anni207,

Bien-Zenker offers a wall system with vital storage bricks that is supposed to regulate humidity.

Since today, due to DIN 1946, it is hardly possible to find a provider who delivers an energy-efficient house without controlled residential ventilation, this wall system could possibly be an alternative, since you can turn off the controlled residential ventilation.

But that would be too risky for me.

The statement that controlled residential ventilation should be omitted because of an eye disease is new to me.

Maybe the ophthalmologist is confusing controlled residential ventilation with a standing fan.

There is absolutely no sensation of drafts in the house, due to the immense air volume of the house compared to the air exchange of the controlled residential ventilation.

And in addition, the air is also filtered.

Regards

AxelF

Hello Axel,
thank you very much for your reply.

I have been in quite a few houses with [Kontrollierte-Wohnraumlüftung] myself and you can clearly feel that air is flowing here!