Blower-Door-Test result (n50=1.13)

Our ancestors still remember frost flowers on the windows and a warm bath once a week, otherwise a cat wash with water from the ship. Not that long ago. Just ask the 70+ generation about their childhood. This is not the topic here. The test (whether sensible or not) is not good. According to our contractors, cleaning and insulation are no longer allowed to change anything about it. That’s why we had two tests, one for airtightness and one for the KFW. The difference for us was something around 0.0x.

I am suspicious of these tupperware-sealed houses, which are then "opened" again with ventilation systems or window rebate ventilations. I wouldn't be surprised if this construction method eventually goes down in building history as a fashion craze.

How did you get exempted from this law for your new building?

I find these Tupperware-sealed houses, which are then "opened" again with ventilation systems or window rebate ventilations, suspicious. I wouldn’t be surprised if this type of construction eventually goes down in building history as a fashion trend.

Why should that be the case? This is simply about controlling airflows. Our ancestors also tried that, but were limited by technology and materials, or it didn’t last long. Car comparisons are always more tangible here: in the past, air flowed into the car while driving, more or less reasonably, and if that wasn’t enough, you just had to roll down the windows. Lovely in winter, wiping windows clear with sponges during the drive, warm air coming out of one hole and icy air from three others… yes, those were the days. The trend that a car is airtight and you control the quantity, location, and temperature, or that the car usually does this on its own, will certainly pass again.

How did you get exempted from this law for your new building?

I did not get exempted, just built outside the KfW standards. We like living with fresh air from outside that smells of forest. We did not do a blower door test. Much more grows on the property than we need for heating.

Energy Saving Regulation Construction also means airtightness

Just because no test was carried out, does not mean that the house is not airtight. That would also mean that the construction company, in your case the carpentry, works less precisely than on a parallel construction site with KFW. The person who did the test for us said that the carpentries here usually achieve 0.6 or better. That is well below KFW, that is passive house standard.