A control Blower Door measurement revealed n50 = 1.4 vs. the design value 0.6. I identified 7 critical leak points; after repairs the building reached n50 = 0.55.
The investor of a passive family house in Brno commissioned a control airtightness test. The design called for n50 ≤ 0.6 1/h, but the first measurement showed 1.4 1/h.
Approach
Measurement followed ČSN EN ISO 9972 (Blower Door):
- Pressurisation and depressurisation in the 50–100 Pa range
- Leak tracing with thermography and anemometer under under-pressure
- Documentation of each leak with photos and location
Outcome
After fixing the seven critical points (penetrations, vapour-barrier laps, door frame seal, around drainage and chimney penetrations, floor-to-wall joint, ventilation grille), the control measurement reached n50 = 0.55 1/h, meeting the passive-house requirements.