The airtightness at 40 Bowhill Lane was measured to be 0.57 ACH @ 50 pascals (air changes per hour at 50 pascals of pressure). The most stringent residential energy efficiency certification program in the world is currently Passive House, which requires houses have an airtightness of 0.60 ACH @ 50 pascals or lower. Let Quik-Therm supply your passive house walls today!