Blower door

Airtightness measurement with blower door measurement method

Energy-efficient construction

In well-insulated buildings, up to 60 % of heating energy can be lost through gaps and cracks in the building envelope. Energy-efficient construction can therefore only be achieved with a high level of airtightness in the building envelope. The blower door measurement method can be used to check the tightness of the building envelope.

Buildings should be free of damage, durable and fit for purpose. The SIA Standard 180 therefore formulates requirements for the building envelope as well as limit and target values for airtightness. For buildings constructed according to the Minergie standard, airtightness measurements are recommended for quality assurance (Minergie®) or mandatory (Minergie-P® & Minergie-A®). Other building labels (DGNB / SGNI / SNBS) also require airtightness measurements for certification.

Even with a positive measurement result (= limit value fulfilled) with regard to the general tightness of the building envelope, a careful check for individual leaks must be carried out in order to prevent any damage (e.g. due to condensation) to critical components.

In addition to airtightness, the quality of the indoor air in Minergie-ECO® buildings must also be checked at the end of construction (acceptance measurements). As a certified sampling point for indoor air measurements we can offer you these two services from a single source.

How does the blower door measurement method work?

The blower door measurement method determines how often the air volume of a building is exchanged per hour at a certain pressure difference to the outside air. In order to build up the differential pressure (negative or positive pressure), a fan is installed in an opening in the building. The output of the fan is regulated in such a way that a defined pressure difference is created between the outside and inside air. The air volume flow characteristic curve is calculated.

In negative pressure mode, leaks in the building envelope can be easily identified by hand, smoke tubes or thermography. In positive pressure mode, air leaks can also be visualized using a fog generator.

Ecosens is a member of the Swiss Thermography and Blower Door Association (theCH)

Our services

We offer the following services in detail:

Blower door measurement technology

Blower door measurement technology can be used to detect leaks in the building envelope and determine the air exchange rate. Possible for single and multi-family houses, apartments, commercial buildings and commercial buildings. Such a test is required for MINERIGE-P and -A buildings.


Pascal Diefenbacher

Head of Indoor Air Quality

Raphael Rapold

Project manager for indoor air quality, blower door specialist

Our references