Many duct systems are excessively leaky, poorly insulated and undersized. Here are some government, utility company quotes on the importance of evaluating your ducts for possible improvement. Replacing your old heating and cooling system with a new high-efficiency system? It is essential that you evaluate the duct system, and if necessary make improvements, to receive anticipated energy savings. A leaky duct system will drag down the performance of the new equipment. A chain is only as strong as its weakest link, and the weak link here is usually the old duct system.

Hear it from the experts:

“Typical duct systems lose 25 to 40 percent of the heating or cooling energy put out by the central furnace, heat pump, or air conditioner. Homes with ducts in a protected area such as a basement may lose somewhat less than this, while some other types of systems (such as attic ducts in hot, humid climates) often lose more. Duct repairs could be the most important energy improvement measure you can do”

– US Department of Energy

“Why would you waste the energy savings from a new efficient air conditioner or furnace by connecting it to a leaky duct system? Properly sealed duct systems will lower your energy bills, increase your comfort and reduce pollution both inside and outside your home.”

– California Energy Commission

“The ducts that are part of central heating and cooling systems offer one of the best opportunities to increase your energy efficiency and your comfort. Studies indicate that 10%-30% of the heated or cooled air is lost—along with the money spent to heat or cool that air—through leaky ducts. Duct testing is strongly recommended when a new heating and/or air conditioning unit is being installed. If the existing duct system is leaky and inefficient before the new unit is installed, it will still be leaky and inefficient after the new unit is installed—unless the ducts are tested and sealed by a qualified contractor. It does not make sense to install a new, energy-efficient heating and/or air conditioning unit unless the duct system is also energy efficient. It is not unusual to find that sealing, repair, or renovation must be performed to complement a comprehensive HVAC installation. Properly sized, installed, and sealed ductwork will make your heating and cooling systems significantly more efficient.”

– Pacific Gas and Electric