Duct systems distribute conditioned air.
Residential duct systems leak 20% or more of conditioned air according to some national studies. This means that 20% of cooling capacity, heating capacity, and utility dollars are going into unconditioned space due to air loss alone. Poorly insulated ducts also cause the air inside the ducts to heat up in summer and cool off in winter before the air reaches the living space inside the home increasing utility costs. Duct leaks also cause pressure imbalances inside the home causing indoor air quality problems.