lufttäthetsmätning

Lufttäthetsmätning, often referred to as blower door testing, is a method used to assess the airtightness of a building's envelope. This process involves using a specialized fan, typically mounted in an exterior door frame, to create a pressure difference between the inside and outside of the building. This pressure difference forces air through any unintentional openings or leaks in the building envelope.

During a lufttäthetsmätning, the fan is operated to depressurize the building to a standard pressure difference, commonly 50 Pascals. The amount of airflow required to maintain this pressure difference is then measured. This airflow rate, when normalized for the building's volume or surface area, provides a quantifiable measure of its airtightness. A lower airflow rate indicates a more airtight building.

The results of a lufttäthetsmätning are expressed as an n50 value (air changes per hour at 50 Pascals) or a q50 value (airflow rate per unit area at 50 Pascals). These values are crucial for various purposes, including energy efficiency assessments, compliance with building codes and standards, and identifying areas where air leakage is occurring. Identifying and sealing these leaks can significantly reduce energy consumption for heating and cooling, improve indoor air quality by controlling drafts and moisture ingress, and enhance occupant comfort. This testing is often performed during construction or after renovations to ensure proper installation of air barriers and to verify the overall airtightness of the building.