Ductwork

Air leakage from ducts can drastically lower the efficiency of forced air systems. Proper sealing and installation of ductwork is extremely important. Standard "duct tape" is not an effective product to seal ductwork. Mastic sealers and foil tape with a butyl rubber backing are superior products. An air leakage test is recommended when sealing ductwork. Leaky areas can be identified and sealed properly when using this device to measure results.

Duct insulation is also important. Metal ductwork should be insulated with R-11 insulation and flex duct should have a minimum of R-8. Flex duct should have gradual bends so air flow isn't restricted.

Connections between sheet metal and flex ducts should be secured with metal or nylon clamps and sealed with mastic or foil tape mentioned above. Flex ducts should be supported with at least one-inch wide supports. Stretch the duct to its full length so air passages are as smooth as possible.

Accurate ductwork sizing and balancing is critical for proper air flow. Heat pump systems require greater air flow and larger duct sizes than forced air systems. Select a contractor who can properly size and install both your forced air system and ductwork.