The only exact method of measuring the leakage of a duct system is to perform the duct pressurization test. This is done by connecting a “Duct Blaster” pressure testing device to the duct system. A large 12” diameter duct and fan are connected to a return inlet of the duct system, the remaining supply and return grilles are taped off, and the test can now begin. The fan “pressurizes” the entire duct system, and special sensors/probes send the pressure reading to a small handheld computer.
This small computer automatically calculates the amount of air loss from your duct system (in CFM or cubic feet per minute). Based on the size or tonnage of your equipment, we can tell what percentage of air loss your duct system has. The higher the percentage of air loss, the higher the cost to heat and cool your home will be.
Leaky ducts not only dramatically increase your gas bills and electricity bills, they lower the capacity of the system by not putting all that conditioned air into the home, but blowing it into your attic. The typical home in America has duct leakage of about 25% to 35%. This means their 5-ton system may be trying to cool the home with only 3 tons, hypothetically speaking. This makes the air conditioner seem to work improperly, run forever without cooling the space, and never gets to the desired temperature on the hottest days.
This high duct leakage also has an even more sinister side effect, bringing indust, dirt, and other attic contaminants into your home. But please know help is available in the form of a Comfort Control technician. By sealing the duct leaks, or replacing the ducting with a modern high efficiency type, the duct leaks can be brought down to below 5%. This can lower your bills by up to 30%, allow your system to cool the home on even the hottest days, and circulate only clean dust-free air in the space.
To find out how much air loss has been stopped is easy and exact by re-testing the duct system after repairs or replacements of the ducting have been done. On new installations, a CA state certified HERS rater is brought in to re-test and independently verify the new duct leakage amount. This is the ultimate in quality control to insure you have a quality duct system installation.