The BlowerDoor test for quality assurance
The BlowerDoor test is a standardised differential-pressure measurement method used to determine the airtightness of buildings. It is used for quality assurance during construction, as a final test after completion, before the warranty period expires, and when refurbishing existing buildings or investigating damage. The test identifies leaks in the building envelope and determines the air change rate.
How the measurement works
A BlowerDoor fan is installed in an external door or window. All other external doors and windows remain closed, while internal doors are opened.
The fan creates a defined negative pressure inside the building. Outside air enters through leaks in the building envelope. The air change rate is then determined. It indicates how often the air in the building is exchanged per hour under test conditions. People can remain inside the building during the test without difficulty.
When should a test be carried out?
A BlowerDoor test is particularly recommended:
- during construction for quality assurance,
- after completion as a final test,
- before the warranty period expires,
- in existing buildings before energy-efficiency refurbishment or as part of a damage investigation.
Testing during construction allows leaks to be detected early and remedied with relatively little effort.
Quality assurance
The BlowerDoor test provides objective information about the airtightness of the building envelope. It helps clients, designers and contractors identify workmanship defects at an early stage and prevent them in the long term.
Conclusion
The BlowerDoor test has been recognised as an established technical practice since 1998 and is a proven method of checking building airtightness. It is used for quality assurance and for final testing in accordance with DIN EN ISO 9972.
Frequently asked questions about BlowerDoor testing
How does a BlowerDoor test work?
During a BlowerDoor test, a fan is installed in an external door or window. It creates a defined negative pressure inside the building, causing outside air to enter through existing leaks. The test determines the air change rate, which describes how often the building's air is exchanged per hour under the specified test conditions.
When should a building's airtightness be tested?
A BlowerDoor test is particularly useful for quality assurance during construction, while the airtight layer is still accessible. A final test can be carried out after completion. Other applications include testing before the warranty period expires, during refurbishment of existing buildings and as part of damage investigations.
How does BlowerDoor testing support quality assurance?
A BlowerDoor test provides objective information about the airtightness of the building envelope. Testing during construction can reveal workmanship defects and leaks at an early stage. As long as the affected components remain accessible, leaks can often be repaired with relatively little effort.