Green Power Living

Professional energy auditors use qualitative and quantitative testing to help measure the amount of duct leakage in air distribution systems. In a typical house about 20 percent of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts.

How It Works

A Pressure Pan is a rectangular pan with a pressure tap that allows it to connect to a pressure gauge. Used in conjunction with a  Blower Door , it is a very useful tool for targeting which ducts are most in need of being sealed.

1. The home is depressurized to -50 Pascal (with respect to outside) with the Blower Door.
2. The technician holds the pressure pan over a single duct register to get a pressure reading in that particular duct run.
3. If the duct run is excessively leaky or partially disconnected, the pressure will vary considerably from the rest of the house (more than -5 Pa with respect to the house).

To measure duct leaks more accurately, the technician may use a Duct Blaster. A Duct Blaster is a smaller version of the blower door, also consisting of a variable-speed fan and a pressure gauge. All supply and return registers are taped close, the Duct Blaster is connected to the air handler to pressurize the system to +25 Pa, and the total amount of duct leakage is determined. Since some duct leakage usually occurs within the conditioned space and is not necessarily bad from an energy standpoint, the Duct Blaster may be used in conjunction with a blower door to measure duct leakage to outside.

1. All duct registers are taped close and the home is pressurized to +25 Pascal (with respect to outside) with the Blower Door.
2. The Duct Blaster is connected to the air handler (or large return register) to pressurize the system to +25 Pa (or 0 Pa with respect to the house).
3. All duct leakage measured is to the outside, or unconditioned space, and represents the heating or cooling energy lost.