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Duct Leakage Impacts on Airtightness, Infiltration, and Peak Electrical Demand in Florida Homes
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Testing for duct leakage was done in 155 homes. Tracer gas tests found that infiltration rates were three times greater when the air handler was operating than when it was off. Infiltration averaged 0.85 air changes per hour (ach) with the air handler (AH) operating continuously and 0.29 ach with the AH off. Return leaks were found to average 10.3% of AH total flow. House airtightness, in 90 of these homes, determined by blower door testing, averaged 12.58 air changes per hour at 50 Pascals (ACHSO). When the duct registers were sealed, ACHSO decreased to 11.04, indicating that 12.2% of the house leaks were in the duct system. Duct leaks have a dramatic impact upon peak electrical demand. Based on theoretical analysis, a fifteen percent return leak from the attic can increase cooling electrical demand by 100%. Duct repairs in a typical. electrically heated Florida home reduce winter peak demand by about 1.6 kW per house at about one-sixth the cost of building new electrical generation capacity.
Cummings, J. B.; Tooley, J. J.; Moyer, N. (1990). Duct Leakage Impacts on Airtightness, Infiltration, and Peak Electrical Demand in Florida Homes. Energy Systems Laboratory (http://esl.tamu.edu); Texas A&M University (http://www.tamu.edu). Available electronically from