Duct Testing

Since mid-2010, Clark County Energy Efficiency’s duct and home performance inspector tested over 700 heating duct systems in Clark County. That adds up to about 1.5 million residential square feet.

Astonishingly, 74 percent of those duct systems leaked enough to qualify for repair incentives from local utility companies.

Save energy, save money

Homes with leaky air ducts are more the rule rather than the exception in Clark County. Leaky ducts account for an average of 20 to 40 percent of your home’s total heating and cooling costs. Depending on the condition and age of your duct system, leaky ducts can easily waste one to two hundred dollars a year!

Sealing and/or insulating your ducts yields the greatest energy savings when compared to other types of energy saving upgrades. On average, it takes three years to recoup the repair costs. Utility repair incentives can cut that time in half.

Cost of duct repair varies with the size and condition of the system. The average duct repair cost for an 1,800 sq. ft. house is between $600 and $1,000.

Common duct problems

Take a look at some of the common duct problems we’ve found during our inspections. Small leaks can be sealed with mastic.

Have a healthier homeair duct

A leaky return air duct within a home’s crawl space can bring mold spores, dust, and even radon gas into your living space. A leaky supply duct in that same crawl space not only wastes your money, but also encourages pests to move into your crawl space, bringing with them germs and disease.

Duct leaks can also draw in potentially lethal combustion gasses from fireplaces, woodstoves, gas and oil furnaces, and water heaters. We strongly recommend that one carbon monoxide detector is installed on each floor in homes that have gas appliances or attached garages.

Duct repair hero

During a recent repair job for an Energy Efficiency Services customer, Adam Salazar, a repair technician from one of our approved contractors, found a ten inch hole in an air return duct that was open to the garage. This was probably the result of an installer forgetting to close off a cut out in the duct that was not needed. Every time the furnace operated, it drew a significant amount of air into the duct system from the garage where paint, pesticides and other toxic substances were stored. These fumes, along with automobile exhaust, were mixed in with the heated air the home’s family breathed.

Not only will this family save a significant amount of money in future energy bills by having their heating ducts repaired, they also had a serious and potentially dangerous defect in their return air duct system corrected that could have produced very negative effects on the family’s health.

Repair incentives

From time-to-time, Clark Public Utilities and NW Natural offer special incentives for duct repair and other weatherization services. If incentives are not available, contact an authorized duct repair service to help or check out the Planet Clark Partners.

NW Natural (through The Energy Trust) does not offer any duct repair incentives. However, they do provide rebates for other weatherization improvements for homes heated with gas systems. You must use an approved contractor to be eligible for these rebates.


View this video and learn how a duct test is actually performed (4 min.). Steve Alexander, Clark County duct and home performance inspector, demonstrates the importance of sealing your ducts.


All forms are PDF files.

Air leakage testing
Duct leakage affidavit for existing construction
Duct leakage affidavit for new construction
Duct testing standards
Ventilation checklist
Whole house ventilation
for homes built after 1990
for homes build after 2010

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