BlowerDoor Measuring Principle

BlowerDoor Testing according to EN 13829 and ISO 9972

BlowerDoor Info

For the measurement, a BlowerDoor fan is installed in an external door or window of the building. All other outside doors of the building remain open. The fan generates pressurization or depressurization. The air exchange in the building is determined. Air change rates provide information on leaks in the building envelope that can be located and systematically eliminated during the BlowerDoor measurement.

Sufficient air-change rates, however, do not mean that the building envelope is free of unacceptably large leakages. Leakage detection – at the very least in the form of spot checks – thus forms an integral part of a BlowerDoor measurement in accordance with EN 13829 and ISO 9972. The energy efficiency of the building and the quality of the construction work are optimized and documented in the test report.

The best known is the BlowerDoor measurement after completion of the building. We recommend an additional BlowerDoor measurement as early as in the construction phase, while the airtight envelope is still visible. This usually allows for eliminating leakages with little effort. If the airtightness test is only conducted with the building in use, improvements require significantly more effort and are more costly.

Construction-related leakages and permeability often occur at joints and penetrations. This is where the airtightness layer should be planned in particular detail in order to avoid later cost-intensive rework.

Typical Building Leakages

Construction-related leakages or permeability often occur at connections and penetrations. When planning an air barrier, these areas should be given careful consideration to avoid costly rework later.

Typical leakages mainly occur in the area of

  • junctions and joint butts of building components    pipe and cable penetrations through the air barrier
  • floor junctions at doors and windows at floor level in converted attics
  • connections of different building materials (e. g. massive/light construction)