Air leakage, Sealing in the home
Air leakage is the leading cause of residential energy loss. A leaky house is expensive because it allows the conditioned air to escape, while literally sucking outdoor air into the house. When the HVAC equipment is running, the house is put under pressure, which accelerates the rate of leakage, increasing the waste of energy, and creating a dusty house.
A house is considered to be sufficiently tight when the air is changing out 3 - 4 times per hour, while under pressure. This allows for healthy indoor air, and minimal energy loss. During an energy audit, we typically find that the houses we test are exchanging the air out 8 - 12 times per hour, while under pressure. This amount of air leakage is extremely expensive and wasteful, but most importantly, it makes it impossible to keep the indoor environment comfortable.
Air sealing a house typically begins with the attic. Can lights, other light fixtures, electrical wiring holes, and open chases must all be covered and sealed to create an effective air barrier separating the conditioned indoor air from the unconditioned attic air. This should be done prior to installing new insulation, if possible.