Leaky air ducts can cost you hundreds of dollars in utility bills every year and can also put you and your family’s health at risk. Contaminants such as mold and dust, excessive humidity, and fumes from aerosols and pesticides are allowed into your home through leaks in air ducts and can really aggravate allergies and asthma.
If you have high utility bills in the summer and winter, rooms that are difficult to heat or cool, or an excessively dusty house then you just might have leaky air ducts.
To make sure that air ducts are properly sealed, first determine if you have leaks. Air ducts are often hidden in walls, ceilings, attics and basements. So, you may want to hire a professional to run a test that will blow air through the duct sealing to determine if there are leaks.
To check for leaks yourself, start by making sure there aren’t any cracks at the connections of vents, registers and grills where they meet with the floor, walls or ceilings.
If you find leaks, seal them with mastic sealant or metal tape. Never use duct tape. Despite its name, it doesn’t work as well for this application.
What you want to do is squeeze a line of the mastic sealant into the bigger opening and then push the other section into the sealant.
Check the duct sealing around the joints where it meets with the heating and cooling units. Then check insulated ducts for streaks of dirt around the seal, this is a sign that there is a leak under the insulation.
Look for kinks in your duct pipes, as this is always a sign of an air leak. Then make sure you’ve checked and sealed all connections between the major air unit and plenum, the furnace and filter slots, all seams, and all joints between duct branches.
Also, check to see if duct pipes are supported every five feet by hanging metal straps. This is supposed to be a standard installation step but is often overlooked. Without it, ducts will detach, sag and leak.