What is a Blower Door?

A blower door is a powerful, variable-speed fan that can be temporarily mounted into an exterior door frame to provide controlled air flow for analysis.  The way that air flows through a building can have a serious impact on air quality, comfort and energy expenses.  The use of a blower door allows air flow through a structure, and the resulting loss of cooled or heated air can be immediately quantified, providing a way to pinpoint the location of air leaks.

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Finding the Problems

Since the blower door forces air through cracks and holes, the locations of the leaky spots can be identified.  The draft of air entering through the holes can often be felt with the hand.  Smoke and infrared imaging can also be employed to locate smaller, more subtle leaks.  It is often assumed, especially by homeowners, that poorly sealed windows and doors are the major culprits of air leaks.  In reality, leaks in other areas are usually much more significant.  The difference in air pressure between the interior and the exterior is greater both at ground level and up high, so leaks in basements and crawlspaces, as well as in attics, are the most important to locate. 

Benefits of blower door tests

 

There are many benefits to blower door tests. Some of the major benefits of running this test in your home are:

  • Discovery of drafts, air-leaks, or lack of insulation

  • Makes your home more energy efficient thus reducing greenhouse gases

  • Reduces your carbon footprint

  • Improves your indoor air quality

  • Increases the value of your home

  • Saves you money on your utility bill

  • and may increase the efficiency and life of your air conditioning and heating system.

  • Controlling outdoor contaminants, pests, and odors from entering your home.

  • Determining proper sizing and airflow requirements of heating and cooling equipment.

  • Determining whether mechanical ventilation is needed to provide acceptable fresh air and maintain indoor air quality in your home