A: Inspection discovers any obvious break in the duct work and, as the initial step of the sealing process, the Aeroseal system will establish an exact amount of leakage in the duct system. Of course, many people already know that a room or two in their house doesn’t get good air circulation because they can feel it. Or, they already know that their energy bill is high because they see it. The diagnostic measurement, provides a scientifically valid means to understand the performance of your air duct system. Many people are surprised to learn that homes typically leak 30% to 40% or more of their air through air duct leaks.