The supply and return ducts in a home are designed to be in balance. This means that the amount of air being supplied is the same as the amount returned to the air handler, and the pressure inside the home is neutral. If either the supply or return ducts have air leaks, this balance is disrupted and the pressure throughout the home can be skewed. Health concerns from leaky ducts Of particular concern to human health is the quality of air drawn into the building by a leaky return duct. If the return duct leak is located near a flue or chimney, it can draw combustion by-products into the home.
Partial correction can worsen the problem Partially correcting duct leakage poses additional risk.
Sealing only some of the leaks can create an unsafe pressure imbalance. Be sure to seal leaks in both the supply and return leaks, and ensure that the pressure inside the house is neutral. FPL can assist you in these efforts with the duct system testing and repair program .