Duct Testing

It's normal to assume that your ducts are carrying conditioned air, but there's a good chance that they can be leaking money away. After all, experts say that over two-thirds of the million miles of ducts in U.S. homes are in need of repair or replacement. Is it worth it to have ineffective ducts? 

In addition to being waste, leaking ducts can be a major source of discomfort for homeowners. Though ducts are a skeletal component of a home which is seldom examined, the implications of a poorly working duct system are incredible, as experts estimate that 25% of total energy loss in homes can be attributed to having ineffective ducts. Given their importance to temperature control, it is essential that ducts work correctly; when ineffective, the temperature can become the opposite of what is desired. Finally, ducts can pull impurities and irritants into your home, which can be detrimental to both comfort and peace of mind.

Though waste of air is definitely bad, leaky ducts also have the potential to cause great discomfort to homeowners. While ducts are a skeletal component of a home which aren't very publicized, they can have a great impact on the ways in which people are forced to spend their money and how comfortable they are. 

Here are some problems that can happen due to leaky ducts:

  • You can be putting air into places that don't need it, like your garage or attic.

  • A result of return leaks, outside air can make its way into the duct system, thereby distorting the desired condition. You wouldn't want cold air combining with your heat on a 15° day, would you?

  • Heat pumps can be affected by duct leakage, which can negate their effectiveness. There is little reason to maintain a heat pump if it isn't working property.

  • The reverse of the aforementioned garage and attic problem — air being taken from those areas — can occur, which can result in junk making its way into your ducts.

  • Unbalanced depressurization can result in accidental transmission of combustible products with leaky ducts.

Measuring Duct Leakage

To see how well your ducts perform, an auditor will pressurize the duct system using a special fan while measuring how air comes back through the fan and its effect on the rest of the unit. With tight ducts, little air is required from the fan to change the pressure: if a duct system is cohesive, air can travel a longer way than if it is not. Ducts affecting both the inside and outside of the house can be tested. These examinations can judge both the overall efficiency of your ducts and provide you with an idea as to where the ducts are leaking.

There are two ways to test the effectiveness of ducts; a Duct Blaster® and a Blower Door.

Duct Blaster

  • The Duct Blaster is the most direct manner in which to test for leaks, akin to the ways in which plumbers can test pipes for leaks.

  • A Duct Blaster fan joins the system at either a return grille or the air handler cabinet. After sealing all openings, the auditor will utilize the Duct Blaster to send air through all imperfections in the system.

  • The auditor will increase the speed of the fan throughout the system until a standard pressure is achieved.

  • To give homeowners an accurate representation of spots of leakage, a "fog machine" can be used to pump (non-toxic) fog through the ducts to indicate the actual spots of leakage.

Learn more about Blower Door Testing.