Duct Leakage

Duct leakage is conditioned air escaping through gaps, bad joints, and disconnected sections of ductwork before it reaches your rooms. ENERGY STAR estimates a typical home loses about 20–30% of the air moving through its ducts this way.

It shows up as high bills, rooms that never reach temperature, and a system that runs constantly. Because the leaks are usually in attics, crawlspaces, and wall cavities, you can't see them — they have to be measured, typically by pressurizing the ducts and reading how much air leaks at a set test pressure.

The fix is duct sealing, by hand with mastic and tape or with an aerosol system like Aeroseal. The reason testing matters is that it turns a vague 'we sealed your ducts' into a verifiable before/after number — proof the leaks are actually gone.