Install the ventilation system outside?

Hello,

Sure, when I open the window, air at 0 degrees comes in, but I only ventilate once a day?

I would definitely not recommend that to you - especially if you are building with ETICS! In the first 2 years, you have to do at least 3 quick ventilations per day, preferably several times.

Best regards from the Rhineland

Hello,

Regardless of the fact that once a day is too little for modern houses, what does an ETICS have to do with ventilation?

Sometimes I really wonder ....

Today's houses are extremely airtight; even with purely monolithic construction. If a classic ETICS is applied to the built stone, it becomes even more airtight, because the exterior plaster must - for stability reasons - be sealed with a synthetic resin plaster. Furthermore, if ventilation - even decentralized ventilation - is omitted, a three-time shock ventilation is usually not sufficient in the first years of occupancy. Even if the stones are glued, water enters the house through the screed. The inhabitants of the house each exhale 1 liter of water per day, they will also shower/bathe a bit; usually cooking is done as well. This water must necessarily be transported out of the house.

With monolithic construction, at least some of the existing moisture in the single-family house migrates outside through the masonry (but only if the walls are not painted with sealing paint).

With classic prefab house construction, the moisture is completely enclosed within the single-family house.

Rhenish greetings

Sorry, but monolithic and also double-shell masonry are just as airtight. The small amount of liquid that can be transported through the walls is in the per mille range of what is produced during the day. Therefore, ventilation should be considered regardless of the type of insulation.