Definition
Duct sealing is closing the leaks, gaps, and loose connections in a home's ductwork, usually at joints, boots, takeoffs, and plenum connections, using mastic sealant or foil-backed metal tape rather than cloth duct tape. ENERGY STAR estimates a typical home's duct system loses about 20 to 30 percent of the air moving through it.
Also called: Duct leakage repair
Why it matters to you
Where ducts run through a damp crawlspace, supply leaks heat the crawlspace instead of the house and return leaks can pull crawlspace or attic air into the air you breathe. Sealing also matters before a heat pump upgrade, because heat pumps are sensitive to airflow and leaky ducts can keep new equipment from reaching its rated performance.
Practical guidance
Dusty registers, uneven rooms, and visibly disconnected crawlspace ducts are worth pointing out to a technician. Leakage testing and sealing with mastic and mechanical fasteners is contractor work; never use cloth duct tape, which ENERGY STAR notes does not last.
About this definition
Written by the Home Energy Group team — a family-owned HVAC company celebrating 25 years of comfort & care across SW Washington and the Portland metro, licensed in Washington (WA LIC# HOMEEGI003J7) and Oregon (OR CCB# 184255). Definitions inform; an on-site diagnosis decides.
