Learning About HVAC Equipment

« Back to Home

3 Ways to Check for Leaky HVAC Ducts

Posted on

Damaged HVAC ducts admit pollutants and leak heated or conditioned air. Both can affect your home's comfort, health, and HVAC efficiency. Below are some ways to check for leaky ducts.

1. Evaluate the Signs and Symptoms

Your HVAC's performance should make you suspect leaky ducts. For example, you should suspect a leaky duct if:

  • Your house is unusually dusty since cracks and holes in air ducts suck in dust that circulates in the house along with heated or cooled air.
  • Your energy bill is unusually high since leaky ducts force the HVAC to work harder than usual, a condition that increases HVAC energy consumption.
  • You experience uneven heating and cooling in the house, possibly due to the ducts leaking heat or cool air.
  • Your HVAC runs lengthy cycles, which might be because of the compromised efficiency due to air losses.

Note that the above signs and symptoms do not prove duct leaks since other HVAC problems might have similar signs.

2. Try DIY Tests

Some DIY tests can help you confirm whether you have leaky ducts. Below are some tests to try.

Check for Visible Damage

Ducts leak air through disconnections, holes, or cracks. Age-related wear and tear, corrosion, improper repair, and accidental damage are some of the things that cause such damage. You might spot duct damage if they are big enough. For example, a disconnected duct joint means you have a leaky duct.

Conduct a Flame Test

The flame test works because even a relatively weak draft can affect a flame. The flame test is viable if you suspect a leak in a specific area. Hold a flame, such as a candle flame, near the suspected area while the HVAC is running. A flame disturbance points to a leak.

You should only try the DIY tests if you can do them safely. That means, for example, that the DIY tests only work with accessible or visible duct sections. 

3. Call a Professional

The best way to confirm a leaky duct is to involve a professional HVAC technician. HVAC technicians have different ways of testing for leaky ducts. One method involves the use of a duct blaster.

The test involves a portable fan that the technician attaches to the duct system during the test. With the duct grilles and registers sealed, the technician turns on the blaster to force air through the duct and leaks. The technician then uses a pressure probe (inserted into the supply duct) and pressure gauge to measure the air flowing through the duct to reveal possible leaks.

Contact a professional HVAC system services contractor for the relevant repairs if a diagnosis confirms the leaky ducts. Remember to expedite the repairs to prevent further complications with your HVAC system.