First of all a very happy new year to all of our clients, business partners, competitors and other readers of this blog.
The new year has started just a few hours ago and since then, the official requirements for the air permeability of new buildings have been lowered to a maximum value of 5m³/m²h, respectively
3m³/m²h in case a mechanical heat recovery ventilation system is installed.
Beside the ongoing confusion about the meaning of the air permeability and the permanent mixing with the air change rate, we believe the new values are still a way too high for an efficient up to
The most European (continent) countries operate with an air change rate of maximum 1.5 air changes per hour for new buildings. Some countries do even have more strict regulations and the Passive
House Standard requires a maximum of 0.6 air changes per hour. All values are specified at 50Pa differential pressure.
We know that the air change rate and the air permeability rate of every building vary slightly (or more), depending on the shape of the building. But after doing some analysis of our own air
tightness tests and some competitors tests, we´re pretty confident that the deviation between the air change rate and the air permeability is not bigger than a maximum value of 0.5 for the most
conventional building shapes. A light house could be completely different, because of the ratio between building volume and building envelope, but we didn´t get a chance for a testing so far.....