Emerging Technologies: Improved Duct Sealing PDF

Nothing is certain but death and taxes—and perhaps, leaky ducts. All ducts have some degree of air leakage but, unlike taxes, keeping leakage levels down to a reasonable level is possible. In practice, however, ducts leak more than they should. Measurements made by Lawrence Berkeley National Laboratory (LBNL) of commercial building duct systems found, on average, duct leakage exceeded the ASHRAE recommended leakage classes by roughly a factor of 20.¹