Duct Sealing

Ducts should always be installed within the boundaries of the building envelope. We often find that building or HVAC designers break this rule and allow ducts to enter unconditioned spaces. When this occurs, the ducts must be sealed to prevent conditioned air, which you are paying to heat or cool, is not lost or mixed with unconditioned air.

This is not just a cost or comfort issue; the dust, pests and other pollutants that enter the living space through leaking ducts can affect indoor air quality, and therefore human health. It will also be a difficult house to keep clean.

Heating and cooling equipment is sometimes installed in inhospitable places such as attics or garages. More often, the air handler is in the right area (basement or dedicated mechanical room within the conditioned space), but the ducts run through the attic or garage to provide more usable square footage within the building. These ducts must be sealed!

Don't be fooled by the wrapping of foil insulation. Underneath the foil, there are large enough gaps in the sheet metal joints to allow whole swarms of cluster flies and dust in one short breath. When we fix ducts using the method seen in the movie, the foam sealant is also insulation with an "R" value of 6.9 per inch.

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