Studies indicate that 10%-30% of the heated or cooled air is lost, along with the money spent to heat or cool that air through leaky ducts. Properly sized, installed, and sealed ductwork will make your heating and cooling systems significantly more efficient. Energy loss is not the only concern. Duct systems can also involve the comfort of your family, employees, tenants, or customers, as well as your indoor air quality. Testing the ducts will locate leaks or damage and focus repair work in the right areas.

What is a Duct Blaster Test ?

A Diagnostic tool designed to measure the air-tightness of forced air heating, ventilating and air-conditioning (HVAC) ductwork. A duct blaster consists of a calibrated fan for measuring an air flow rate and a pressure sensing device to measure the pressure created by the fan flow. The combination of pressure and fan flow measurements are used to determine the ductwork air-tightness.

When to perform Test?

At Final (total leakage)

  • Most accurate, but hardest to troubleshoot
  • Best choice for ducts located in an area that will be accessible at final (unfinished basement, unconditioned attic, etc)

At rough-in with air handler (total leakage)

  • Easier access to troubleshoot, but should always come back and visually verify that boots are sealed to subfloor/drywall.
  • Desirable if ducts will be inaccessible later

At rough-in without air handler

  • Least reliable as a quality indicator, visual verification of sealed boots and air handler needed.
  • Avoid if quality duct installation is your goal.

Ducts or air handler outside conditioned space:

  • 2009 IECC:
      • Post construction
  1. 8% leakage to outdoors OR
  2. 12% total duct leakage
  • At rough-in
  1. 6% total duct leakage with air handler OR
  2. 4% total duct leakage without air handler
  • 2012 IECC:
  1. 4% Total duct leakage at completion
  2. 4% total duct leakage at rough- in with air handler
  3. 3% total duct leakage at rough-in without air handler

This is not difficult to achieve if you address the major sources of leakage.