Evaluation of residential duct sealing effectiveness.

The purpose of this project was to evaluate duct sealing as a means of reducing the energy consumption of hot air distribution systems in central Pennsylvania houses. Five houses were studied, all of which were heated with forced-air electric heat pump systems. During the winter of 1995, the heat pump energy consumption, supply air temperature, and the temperature at the thermostat were monitored continuously for approximately two months prior to the duct retrofit. A test also was performed to measure the leakiness of the ductwork. The ducts were then sealed, concentrating on duct leakage to unconditioned spaces. After the duct-sealing project was completed, another test measuring the leakiness of the ductwork was performed to determine changes in duct leakage characteristics. Finally, the heat pump energy consumption was monitored for another month. Energy consumption was then corrected for weather changes, and the results were compared to the results from the previous two monitoring periods to determine the impact of the duct-sealing retrofit on energy consumption. Based on the heating loads during the two monitoring periods, it was found that the retrofit had a significant impact on energy consumption in only one of the houses studied