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The Importance of the Blower Door Test on an Energy Audit
You hear a lot about energy audits on homes and commercial buildings to determine what is required to make them more energy efficient, but it's not always clear what this entails or how the outcome is rated. One of these tests is designed to find out how airtight your house is and what needs to be done to improve it.
The Too Tight Theory
Forty years ago, it wasn't unusual to hear talk of houses being too tight. There was some concern about the air quality inside if a house didn't "breathe." Of course, we know today that a house can never be so sealed up that you have to open a window to breathe. HVAC systems are designed so that a house receives outside air all the time.
What you don't want are air leaks at windows, doors, ceilings, and other exterior barriers. The tightness of the house has to do with more than just heating and cooling costs. Other concerns are moisture condensation, air quality, drafts, and air leakage. The airtight home is more comfortable to live in than the airy type.
The blower door test is an ideal way to identify the leaks in a home or business so a plan of action can be formed on how to best address them. It is a relatively simple process to set up the test with the right equipment. An exterior door is opened and fitted with a frame that has an opening just large enough to accommodate a powerful fan.
With all other exterior openings closed, the fan is turned on blowing outwardly to create a vacuum in the house. As this occurs, the higher pressure on the outside of the house will find ways to get back inside. While this process is taking place, technicians monitor where the air is entering the building. This can be done with a smoke pencil, which will locate any infiltrations.
A calibrated blower door does more than just pull air from a building; it can measure the amount of air pulled out of the house and provide enough information to determine if the home is as airtight as it should be.
All houses have air leaks if they have any kind of exterior openings. The blower door test determines if those leaks are a problem and where the majority of outside air is entering a building. Then the best solution can be determined to make the house or structure more energy efficient.