Blower-door testing is a very adequate way of checking your home for air leakages. The blower door is an instrument that consists of a panel with a built-in fan that will fit into the opening of your doorway; it is designed to fit any size doorway.  Most often, the test is performed using an exterior door. The fan will pressurize your home to a standard pressure. There are several different gauges that are used to help you monitor the pressures throughout your home to help you find air leaks that are present in your home. Blower-door testing will help professionals to determine if air-sealing work in your house is necessary. If the building needs to be air-sealed, a blower door helps to locate these specific spots.

The blower-door setup includes:

• a frame and flexible panel to install and seal the doorway.
• a variable speed fan that will adjust itself according to the inside pressures.
• a pressure gauge for determining the difference between the outside and inside pressures.
• a manometer for measuring large air flow volumes.
• hoses for attaching the manometer to the outdoors and the airflow manometer to the fan.

Compare blower-door testing to inflating a large beach ball that has a leak. When you inflate the ball, it will not take much air to inflate it if it has no leaks. But try inflating the ball if it is full of pin holes or just one large hole. It will take a steady stream of air to keep it inflated. The same thing occurs in your home if you have air that is always escaping—your home will always be at work replacing the air it loses. You will be losing cooled air in the summer and heated air during the winter. Not only are you losing air, but your HVAC or heating unit is running more to replace the air you have lost.

Air pressures in each room of your house can be monitored during a blower-door test. While the blower door is running, you can see how air is escaping from each room. This is the same thing that happens while your air exchanger is running. While the blower-door test is taking place, at some point the operator will put your house through many different scenarios that it could be subjected to in everyday usage.

We know that air moves from high pressure to low pressure. If you have gas appliances, this is a very big issue. The blower-door test can determine if your appliances are properly vented. This is very important because, if the pressure in your house is too low, then there could be a draft pulling the gas fumes back into your house causing carbon monoxide to enter your home. This could be very dangerous! Please check to see if blower-door testing service is available in your area. If you do not know anyone, your local HVAC contractor can assist you in this area.