Depressurization Using a Blower Door
The Blower Door is a diagnostic tool designed to measure the airtightness of buildings and to help locate air leakage sites. Air leakage in a building represents can account for as much as 40 percent of a home's heating and cooling costs.
The Blower Door consists of a powerful, calibrated fan that is mounted in a self-contained frame and temporarily sealed into an exterior doorway. The fan blows air into or out of the building to create a slight pressure different between inside and outside. The pressure created simulates 20 mph winds on all four sides of the building. This pressure difference forces air through all holes and penetrations in the exterior envelope. By simultaneously measuring the airflow through the fan and its effect on the air pressure in the building, this test measures the airtightness of the entire building envelope. The average home has enough small air leakage sites that as much unplanned for outside air moves through the house as if a small window is left open all year round.
Blower Door tests can be used for a variety of purposes including:
- Locating direct and indirect air leaks
- Documenting the construction airtightness of buildings
- Estimating natural infiltration rates in houses
- Measuring and documenting the effectiveness of air sealing activities
- Measuring duct leakage in forced air distribution systems
- Determining the need for ventilation equipment
Because the Blower Door forces air through all holes and penetrations that are connected to the outside, those problem spots are easier to find using chemical smoke, an infrared camera or in the case of a large leakage area, simply feeling with your hand. These air leakage paths are found and then documented by the rater to provide recommendations and solutions for air sealing work. Just as importantly, blower doors can help diagnose which parts of a house do not need to be sealed.
We can return when you are having the air sealing work done or when it is completed, and set up the Blower Door test again, providing you with feedback on the effectiveness of the work.
Balancing Pressurization in Duct System
Using a device called a Duct Blaster, we use pressure testing to find the amount and location of air leakage in your home's duct system. To do the test, we use specially designed tape to seal all the outlets except for one on the return side of the system (the side that returns stale air to be reconditioned). The Duct Blaster is connected that last one and then turned on to bring the duct system to the same pressure as we have created in the house with the Blower Door. This compensates for any air leakage from the duct system.
We are thus able to measure the air leakage to the outside, leakage which can account for as much as 30% of your heating and cooling costs. Improving the efficiency of ductwork is the single most important energy measure for most homes, and one of the least expensive to do.