Blower Door Test


Blower door testing is the universally accepted method to check air tightness in buildings. The blower door test is a simple yet extremely efficient way to measure the quantity of air entering a building and also where to find the air leakage areas. By performing this test, we are able to know the amount of warm air that is leaving the building and to find and seal the air leakage areas.

Blower Door Testing Procedures

  • Door panel system – seals fan between inside and outside
  • Calibrated fan – pressurizes or de-pressurizes building through door panel system
  • Measures pressure and flow

CFM50 – Cubic Feet per Minute of air flow through the fan to create a pressure differential of 50 Pascals

Why 50 Pascals? It is the inside to outside pressure difference created by a 32.2 km/h (20 mph) wind on exterior surfaces equally.

ACH50 – Air Changes per Hour @ 50 Pascals

ACH @ 50 Pa

  • Energy Tight houses – 1.5 or lower
  • Tight – 1.5 to 3.57
  • Average – 3.57 to 4.55
  • Leaky – 4.55 – 10.35
  • Newer properties should be tighter