Air leakage, also called air infiltration accounts for as for as much as 60% of the total heat loss in a typical home. The less your home's air leakage, the lower your utility bills. View the following videos of why one should use spray foam insulation: Go to www.finehomebuilding.com/pages/subscription/how-to-air-seal-attic/video-01.asp. If you are prompted to login, use email@example.com as the email and qwertyui as the password. Black Bear Construction insulates with spray foam insulation to prevent air infiltration and leakage.