What is duct leakage, how is it tested, and what are common remedies?

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Multiple Choice

What is duct leakage, how is it tested, and what are common remedies?

Duct leakage is air escaping from the duct system into unconditioned spaces, which wastes conditioned air and lowers system efficiency while causing comfort and humidity problems. To know how much is leaking, a duct leakage test is used. This test typically employs a duct blower or duct blaster to pressurize (or depressurize) the entire duct system and measure how much airflow is needed to hold a set test pressure. By comparing the measured flow, you can quantify total duct leakage and leakage to outside, which tells you where and how much repair is needed. The common remedy is sealing the joints and seams of the ductwork using durable duct mastic or sealant and then finishing with the appropriate tape (often UL-listed foil or metal tape) at connections and transitions. This creates a continuous, airtight path and prevents leaks from developing again. After sealing, another leakage test is usually performed to verify the improvement. Sealing is far more effective for restoring efficiency than simply increasing fan speed, and leaks that aren’t addressed will continue to waste energy.

Duct leakage is air escaping from the duct system into unconditioned spaces, which wastes conditioned air and lowers system efficiency while causing comfort and humidity problems. To know how much is leaking, a duct leakage test is used. This test typically employs a duct blower or duct blaster to pressurize (or depressurize) the entire duct system and measure how much airflow is needed to hold a set test pressure. By comparing the measured flow, you can quantify total duct leakage and leakage to outside, which tells you where and how much repair is needed.

The common remedy is sealing the joints and seams of the ductwork using durable duct mastic or sealant and then finishing with the appropriate tape (often UL-listed foil or metal tape) at connections and transitions. This creates a continuous, airtight path and prevents leaks from developing again. After sealing, another leakage test is usually performed to verify the improvement. Sealing is far more effective for restoring efficiency than simply increasing fan speed, and leaks that aren’t addressed will continue to waste energy.

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