lufttetting

Lufttetting refers to the design, execution and maintenance of an airtight building envelope in order to minimize uncontrolled air leakage. The goal is to reduce heat losses, increase energy efficiency and improve indoor comfort by preventing drafts and temperature fluctuations. A tightly sealed envelope is typically complemented by a controlled ventilation system to ensure adequate indoor air quality.

Achieving lufttetting involves creating continuous air barriers across the building envelope and detailing joints, seams, penetrations and connections with suitable materials. Common methods include the use of airtight membranes or fluid-applied sealants, tapes, gaskets and foam where gaps occur around windows, doors, pipes and electrical penetrations. The work requires careful coordination among trades to avoid gaps and damage to the air barrier during construction and renovation.

The effectiveness of lufttetting is assessed with air-permeability testing, most often a blower door test conducted according to standards such as ISO 9972 or EN 13829. Results are expressed as air changes per hour at 50 pascals (ACH50) or similar metrics, providing a quantitative measure of building airtightness. In many regions, energy codes and performance standards set target levels for new and renovated buildings, with particularly low leakage for passive or near-zero energy designs.

Potential drawbacks include moisture and condensation risks if ventilation is not properly managed, as extremely airtight buildings require well-designed mechanical ventilation with heat recovery. Durability and long-term performance depend on good detailing, quality workmanship and regular inspection to ensure seals remain intact over time. Lufttetting is thus a balance between minimizing unwanted air movement and maintaining healthy indoor environments.