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HVAC ductwork problems can go unnoticed for a long time, but the efficiency of an air delivery system directly influences the performance of your air conditioner, furnace or heat pump. You may be losing as much as 30 percent of your conditioned air as a result of faulty or leaky ducts, according to the U.S. Department of Energy.
The ductwork in an HVAC system consists of a long, branching group of duct pipes that snake throughout your home, hidden behind walls, in ceilings and floors, or in the attic. Because the majority of the HVAC system is hidden, homeowners often have a hard time determining ductwork’s condition. And over time, connections can loosen or ducts can incur damage.

Most often, ductwork problems require the help of a professional, but here are a few problems you can self-diagnose on your HVAC system.

Uninsulated ducts

When a portion of your HVAC system travels through areas that don’t have access to cooled (or heated) air, like your garage or attic, cool air moving through the ducts will succumb to the hotter attic air surrounding the duct pipes. In the winter, heated air can cool off for the same reason. This is easily fixed by insulating ducts.

Damaged ducts

A variety of factors can lead to damaged ducts, such as connections breaking lose, human interference or poor installation. If conditioned air leaks out of the ducts, you’ll pay for it in terms of higher energy costs. Seriously damaged ducts may require that you replace a portion of the HVAC ductwork system.

An efficient HVAC ductwork system relies on a balanced supply of air sent into your home, along with a healthy amount of return air that moves back into your HVAC equipment. The return-air portion of ductwork is particularly prone to problems such as a lack of adequate return grilles, and the system is prone to leakage too. Proper inspection will identify the root of ductwork problems.

There must be an equal amount of return air to support the supply air ducts. For every ton of air conditioning capacity there must be 400 cubic feet per minute of air volume available in both return air duct and supply air.