CH-03-07-3 -- Air Handler Leakage: Field Testing Results in Residences PDF

Testing was performed to characterize air leakage in 30 air handler cabinets and at connections to supply and return ductwork. Operating pressures were measured in the air handler and plenums. Q0.1 (Q25) in the air handler averaged 23.9 cfm (11.3 L/s) in 30 homes. Leakage at the return and supply ductwork connections averaged 3.9 Q0.1 (1.8 L/s Q25) and 2.2 Q0.1 (1.0 L/s Q25), respectively. Actual return side leakage of 77.5 cfm (36.6 L/s) and supply side leakage of 3.1 cfm (1.5 L/s) are calculated based on Q0.1 (Q25) and measured operating pressures, which are 6.4% of the system airflow.

Duct leakage (including the air handler) was also measured in a subsample. Return Q0.1 (Q25) for 21 homes was 88 cfm (42 L/s). Supply Q0.1 (Q25) for 11 homes was 132 cfm (62 L/s). Return leakage is estimated to be 170 cfm (80 L/s) or 13.4% of system airflow and supply leakage is estimated to be 167 cfm (79 L/s) or 3.2% of system airflow.

Units: Dual