lufttette

Lufttette is a term used in Scandinavia to describe the property of being airtight, especially in relation to building envelopes and components. It refers to the degree to which unintended air leakage is minimized through walls, roofs, windows, doors, and penetrations. Achieving lufttette construction is central to energy efficiency, thermal comfort, and moisture control.

Measuring lufttette often involves a blower door test, which pressurizes or depressurizes a building to quantify leakage. Results are expressed as Q50 (volume of air leakage at 50 pascals) or ACH50 (air changes per hour at 50 Pa). Standards and guidance for measurement include European norms such as EN ISO 9972 and EN 13829, as well as national building codes. In many Nordic and European contexts, targets for lufttette are set to support low-energy or passive house performance, with ACH50 values commonly aiming for around 0.6 h-1 or lower in efficient buildings.

Techniques to achieve lufttette include designing continuous air barriers, careful detailing around joints and penetrations, high-quality seals for windows and doors, and proper installation of insulation and vapor barriers. Sealing around pipes, cables, and electrical outlets is also essential to reduce leaks. Once airtightness is improved, controlled ventilation becomes necessary to maintain indoor air quality.

Benefits of lufttette construction include reduced heating and cooling losses, fewer drafts, and improved comfort. However, excessive airtightness without adequate mechanical ventilation can lead to moisture buildup and poor indoor air quality, so balanced ventilation systems with heat recovery are typically employed in lufttette buildings.

Etymology-wise, the term derives from Germanic roots meaning air and tight, and is commonly used in Scandinavian languages to describe airtight construction and performance.