A blower door test shows the total amount of air leakage in a home. Having a tighter home improves energy efficiency, and saves money on energy bills.
The building tightness standard for Montana is targeted at 4 air changes per hour (measured at 50 Pascals pressure control), or 4 ACH50.
How it Works.
The blower door fan and nylon door panel are temporarily sealed into an exterior doorway. The blower door fan is used to blow air into or out of the building, creating either a positive or negative pressure differential between inside and outside. This pressure difference forces air through all holes and penetrations in the building enclosure. The tighter the building the fewer holes there are. A measurement devise called a manometer is then used to measure the pressure differential across the fan and building envelope.
Blower Door Builder Checklist
Scheduling & Project Preparation for Test
Please have building plans on site and all door knobs and weather stripping in place when the test is scheduled. We prefer that all drains/p-traps have had water ran through them, but it is not necessary if there’s a scheduling conflict with the plumber. If there are any special features that may affect the test; please make a note of it when scheduling the test.
When testing additions on existing structures a clear air sealed division between the existing and new structure is required for the test. This may require the builder to temporarily seal off building sections or hall ways with plastic. In the event the addition does not have an exterior door or window that can fit the blower door the builder will need to provide an opening at the common wall/hall in which the blower door can be setup. The maximum blower door size has a width of 3ft 9inch and a height of 8 ft. The minimum door size has a width of 2ft 4inches and a height 4ft 5 inches.
Please keep in mind when testing multi-family that air infiltration into adjacent units counts against that units air filtration. We suggest special attention be taken on common walls and that they be treated as an exterior wall when it comes to air sealing.
Home Owners
Homeowners, a blower door test is an ideal place to start when trying to identify areas of improvements to reduce energy consumption and savings on utilities. With the assistance of a blower door, air infiltration areas can be identified for remediation within your home, protecting your investment and offering a measurable pay back in reduced energy bills. Is your home producing moister on interior windows? A blower door test can be used to determine if its your windows or if your home doesn’t have adequate ventilation.
