Who needs Blower Door Testing?
Effective July 1, 2017 all new residential construction will need to pass a mandatory blower door test before a certificate of occupancy will be issued. This will apply to all residential building permits issued AFTER July 1, 2017.
- Each house/unit pass a Blower Door test (Envelope Leakage Test) with 7 air changes per hour – 7 ACH(50) – or less and that the Blower Door Tested value must be equal to or lower than that which was entered on the R405-2017 Energy Compliance Form
- Mechanical Ventilation is implemented for houses that test at 3 air changes per hour – 3 ACH(50) – or less for the Blower Door Tests
What is a Blower Door Test?
The purpose of Blower Door Testing is to measure the air tightness of a home and check for air leakage. A blower door is a powerful fan that mounts into the frame of an exterior door. The fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and openings. The auditors may use a smoke machine to detect air leaks. These tests determine the air infiltration rate of a building. During the Blower Door Test the house will be depressurized to 50 pascals (the equivalent of a 20 mile an hour wind on all sides of the residence). The auditor then makes various calculations from the Blower Door Test in order to give you the results. Blower doors consist of a frame and flexible panel that fit in a doorway, a variable-speed fan, a pressure gauge to measure the pressure differences inside and outside the home, and an airflow manometer and hoses for measuring airflow.
The importance of Building Envelope tightness.
Air leakage occurs when air comes through cracks, gaps, or holes in the building envelope or air barrier. Air leakage can increase heating and cooling costs by over 30% and directly contribute to health, safety, and comfortability issues. Air leakage can increase the humidity of the building, trap moisture in the air barrier, and allow contaminants to enter the conditioned space. If not remedied quickly, trapped moisture can lead to dangerous rot and mold in the buildings infrastructure which decreases its durability and can lead to expensive repairs and possible health issues down the road.
These are just a few reasons for establishing the proper building tightness:
- Energy Efficiency
- Detect & Repair Drafts or Leakages
- Indoor Air Quality
- Moisture Control
- Code Compliance
- Reducing energy consumption due to air leakage
- Avoiding moisture condensation problems
- Avoiding uncomfortable drafts caused by cold air leaking in from the outdoors
- Determining how much mechanical ventilation might be needed to provide acceptable indoor air quality