Description

Blower Door Airtightness Test (EN 13829 / ISO 9972) — EnerPHit Deep Retrofit in Viladecans, Barcelona

As part of a deep energy retrofit of a single-family terraced home in Viladecans (Barcelona), we carried out a whole-building airtightness assessment using a Blower Door test in accordance with EN 13829 (now superseded by ISO 9972). The testing verified the building envelope performance and supported certification to the Passivhaus EnerPHit standard.

The project was designed by Daniel Tigges (Tigges Architekt) and achieved EnerPHit certification, demonstrating excellent airtightness and high-performance retrofit detailing.

Two-stage airtightness testing

To ensure robust results and enable targeted improvements, two Blower Door tests were completed:

1. Preliminary test (during construction):
   Air leakage paths were identified and traced using a handheld smoke generator and anemometer, allowing the team to locate and address leaks before finishes were completed.
2. Final test (upon completion):
   The completed dwelling was retested to confirm airtightness targets and overall envelope integrity.

Result

The final measured airtightness was:

N50 = 0.55 h⁻¹ This result is well below the minimum requirements of Spanish building regulations (CTE DB HE-1 2019) and is approximately 45% better than the EnerPHit limit for existing buildings (N50 ≤ 1.0 h⁻¹). In practice, this level of airtightness supports improved thermal comfort, reduced uncontrolled ventilation heat loss, and more predictable ventilation performance.