Technical information

Building infiltration

Building air tightness

Building airtightness tests are required in order to get an A, A+ and A++ building energy efficiency certificates. To achieve the required level of airtightness you may need to conduct specific tests using specialized equipment.

In order to accurately measure the airtightness of a building, professional building energy auditors use precisely calibrated blower door equipment. However, performing an airtightness inspection is not exclusive to newly constructed building as it may greatly benefit an older building as well. Several benefits of increased airtightness:

  • Lowered heating expenses.
  • Dew point prevention.
  • Eliminated indoor cool air.
  • The test will also help you determine whether you need a recuperator and how powerful it has to be.


Blower door operation

A building airtightness measurement device is basically a powerful fan attached onto a frame which is mounted into one of the building’s exterior doors. With the use of this fan, air is then being sucked out or pushed into the room. If the air is being sucked out of the building, then an overpressure is created outside (relative to the inside) and air begins to escape out of the building through all of the leakage points. Using a smoke emitter or a thermal camera, precise locations of these leakage points may visually determined.

Blower door systems consists of an adjustable frame, which may be fitted into a door frame, an adjustable speed fan, precision manometer, used to measure pressure differences and electronic components congaing the necessary software.

There are two types of blower door equipment – calibrated and non-calibrated. It is very important to ensure that the auditors preforming an airtightness test is using calibrated equipment with a valid calibration certificate, as measurement results obtained using non-calibrated equipment are unreliable, legally inadmissible and may not be used when obtaining certificate of building energy and class efficiency.

In other words, such equipment may only be used to get a rough idea if you have air leakage in your building. In order to determine whether you need air tightening or additional ventilation calibrated blower door equipment must be used.


Blower door test

Before conducting the measurement, there are several recommended steps that will help you ensure the measurement results are accurate:

  • In case you have a fireplace, ensure that the fire is extinguished and the fireplace is clean of charcoal and ashes.
  • Close all exterior doors and windows and open all of the doors inside the building, seal all vents, chimney shutters and other such openings.
  • During the test, you may have to go room to room and open up or move cupboards, built-in wardrobes, dressers etc.
  • Typically, conducting the measurement takes over an hour, depending on size and type of the building.
  • When measuring airtightness of a newly built building, it is recommended to preform the test before doing any of the interior finishing work. This way you will be able to easily locate and repair any of the leaks without damaging the finishing or decorations.

If an air tightness test is done correctly and appropriate measures are taken to eliminate air leakage points, the financial gain will be evident during the first months of heating.


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