Insulating the Home
Air leakage, or infiltration, occurs when outside air enters a house uncontrollably through cracks, gaps, and openings. Most homes have the equivalent of a large open window in combined air leaks in their attic alone!
Many air leaks and drafts are easy to find because they are easy to feel — like those around windows and doors. But holes hidden in attics, basements, and crawlspaces are more difficult and a bigger problem.
In the illustration on the left, this shows the warm air generated by the heating system rising into the attic around recessed lights, ceiling fans, attic access doors, and registers. Unfortunately, the homeowner is paying to heat their attic! This is not something any of us want to do.
Up in the attic, there are always large holes and gaps that the builder never sealed and you’d never know about. As an example, the picture on the left is a chase that was likely intended to hold pipes and wires that run from the attic to the first floor. Unfortunately, not only is it not being used but it allows air to freely move back and forth between the attic and the living space of the home (this is not what you want).
Blue areas are cold air and yellow and red areas are hot air. This particular image was taken in the summer to illustrate how cold air created by the air conditioner is making its way to the attic. All of this cold air is being lost from the living space and being blown into the attic. In the winter, the reverse process takes place. Warm air created by the heater rises into the attic. Recessed canned lights are also a major source of air loss, particularly when there are 10, 20 or even 30 of them in the home. Air not only leaks around the opening but also through the fixture itself.
To find these penetrations, we use blower doors and infrared cameras. These tools are highly effective at detecting hidden air movement and thermal deficiencies.