The purpose of this project was to evaluate the effectiveness of an add-on control device designed to improve occupant thermal comfort when installed on standard residential air-source electric heat pumps. The device was not expected to incur an energy penalty compared to normal heat pump operation. This experiment evaluated both occupant comfort and energy consumption. An add-on control device designed to proportionally control supplemental electric heating coils was installed on seven heat pumps in central Pennsylvania. During a five-month period between October 1994 and March 1995, the device was switched on and off for alternating week-long intervals. Energy consumption was measured continuously using portable data loggers, and occupant comfort was assessed with a questionnaire filled out by the occupants at the end of each monitoring period. Results of the study indicate that the device may save energy. For the houses tested, an average savings of 10% was recorded. The device also improved the homeowner's perception of comfort in some of the test houses.

Units: I-P