Did you know the average air conditioning system in America is only 58% efficient?

One of the main causes is duct-work. Studies indicate that duct leakage can account for as much as 25% of total home energy loss, and in many cases has a greater impact on energy use than air infiltration through the building shell. Just as important, duct leakage can prevent heating and cooling systems from doing their job properly, resulting in hot or cold rooms, and humidity problems. Worse yet, duct leaks can create air quality problems by pulling pollutants and irritants directly into the house.

How do I know if my ducts are leaky?

Two different types of performance testing systems are used to measure duct leakage Duct Blaster® and a Blower Door.

Blower Door Testing

Blower Door Test

Blower Door Test

  • The Blower Door is a whole house testing system which indirectly measures duct leakage by pressurizing the entire house to a standard testing pressure.
  • By comparing the whole house test before and after all registers are temporarily sealed, the Blower Door provides you with an estimate of duct leakage to the outside.
  • With the Blower Door running, duct leaks can be pinpointed using a hand-held smoke puffer, or a leak detection tool called a pressure pan.
  • In addition to diagnosing duct leakage problems, the Blower Door can identify building envelope improvements that will reduce energy use and increase comfort.
  • Blower Door airtightness measurements can also be used in HVAC equipment design and sizing decisions, and to help estimate the need for air conditioning and heating.

Duct Blaster®

Duct Pressure Testing

Duct Pressure Testing

  • A Duct Blaster is used to directly pressure test the duct system for air leaks, much the same way a plumber pressure tests water pipes for leaks.
  • The Duct Blaster fan is first connected to the duct system at the air handler cabinet, or a return grille. After temporarily sealing all remaining registers and grills, the Duct Blaster fan is turned on to force air through all holes and cracks in the ductwork.
  • The fan speed is increased until a standard test pressure is achieved in the duct system. A precise leakage measurement is then made using an airflow and pressure gauge connected to the Duct Blaster system.
  • Estimates of efficiency losses from duct leakage can then be made from the leakage measurements.


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