Some household air leaks are so small you don't even know they're there, but when you add them all up, they can pose a major threat to energy efficiency. If you're concerned about this energy loss, you may be able to locate and seal the smallest of leaks with a special test called a door blower test.
A door blower test is an important part of any household energy audit, and is designed to pinpoint the locations of drafts while measuring the overall air tightness of a home.
To perform the test, technicians install a temporary barrier across one of the home's exterior doors. The barrier has a built-in fan that pulls air out of the home at about 10 to 15 mph, reducing the indoor air pressure. The barrier also features measurement instruments and gauges to provide air pressure data that might guide future decisions to replace drywall, windows, door seals or other components.
While the home is depressurized, the higher relative pressure outside will drive air indoors through even the tiniest of cracks. During this test, technicians can carefully walk through each area of the home using a tool called a smoke pencil, which emits a thin, steady stream of odorless smoke.
When a technician passes through an area with an air leak, the increased air flow created by the door blower test will disrupt the smooth flow of smoke. Just finding the leak is often the hard part -- a simple application of caulk, spray foam insulation or other sealant can finish the process and dramatically improve the energy efficiency of a room.
Repairing these leaks will also help in other ways, including keeping moisture out of the home and preventing unwanted pests from getting inside.
If you're planning on scheduling a blower door test of your home, there are a few preparations you will need to make:
Batten down the hatches. The flow of air through your home during the test will be gentle, but it will be enough to blow around small particles and paper. Secure anything that might be disturbed, and clean up anything you wouldn't want blowing all over your home, such as fireplace ashes.
Disable appliances that could create sparks or flames. This includes your oven and any appliance with a pilot light. A home auditor will know which appliances need to be disabled for the safe administration of the test.
Open and close. To perform the test, all doors, windows, dampers and other openings to the outdoors must be closed. But on the inside, all interior doors must be opened, including doors to closets and cabinets.
Depending on your home's size, layout and appliances, conducting a blower door test could take two hours or more. But it can provide invaluable information to homeowners who want to do everything they can to make their homes more tightly sealed. For more ideas on how you can get more for your HVAC dollar, reach out to your local climate control experts.