Leaks in the ducts of HVAC systems are quite common and even more invisible than air leaks around windows and doors. Why are they more invisible? Because duct system air leaks are in places people usually don’t go – like the attic or crawlspaces of a home. The most common place for duct system air leaks is near the HVAC unit itself or in the joints of the duct system which are normally in the places just mentioned. Homeowners with leaky duct systems are not getting the full benefit of their HVAC system and may come to the false conclusion that they need a new system.
Detecting leaks in the HVAC system is possible with a Duct Air Leakage Test. The machine used in this test is sometimes called a “Duct Blaster” which sounds ominous but it’s simply a small fan that attaches to a flexible and expandable pipe (that resembles flex duct) that blows air into the duct system and allows a qualified technician to find any and all air leaks so they can be sealed.
Keep in mind that all duct system leaks are NOT the same. Duct leaks in the attic or other unconditioned places are the highest priority because you never get any benefit from those kind of leaks. However, duct system air leaks inside your interior walls or between conditioned floors are not so bad as the leaks will still work to heat or cool the home even if it doesn’t complete it’s trip through the duct system.