Load-based, Climate-specific Testing & Rating Procedure for Heat Pumps and Air Conditioners

The relevance of Heating Seasonal Performance Factor (HSPF) and Seasonal Energy Efficiency Ratio (SEER) ratings as realistic performance metrics to represent savings has been increasingly called into question, and concerns included substantial variations in equipment performance when installed in climates that differ substantially from those used for the ratings. Further, in-field monitoring consistently suggested that current ratings do not predict installed performance well. Field data gathered indicates that existing metrics are not reliable, particularly for modern, variable-speed heat pumps and air conditioners that are expected to be more efficient but don’t always live up to their ratings. Moreover, these systems’ built-in firmware—the internally programmed set of operating instructions—canhave a significant impact on their real-world performance, yet the firmware operation is explicitly excluded from current rating procedures. That firmware affects how the system responds in the field to calls for heat, defrost, part load, preheat and other events that are not present in current full load test procedures. Energy savings estimates are impacted by the accuracy of the rating used. A rating metric that is more representative of in-field performance can significantly improve energy savings achieved by incentive programs or other promotions of high-efficiency heat pumps and air conditioners. An improved metric could significantly increase savings, substantially improve heat pump utility program realization rates, provide better quality information to a wide range of stakeholders, and reduce wasted spending of program resources on under-performing models. Current regulatory test procedures include an optional test at 5ºF (-15 ºC), but such test data is currently not widely available. Utilities, in cold climates concerned about winter peak loads, might be tempted to use heating efficiencies at the 5ºF; however, peak winter demand is more typically dependent on the lockout temperature at which supplemental heating, from electric resistance heating or fossil fuel, is prevented. Allowing equipment to operate under its native controls can significantly increase the accuracy of peak load requirements. Better metrics based on cold-weather and part-load performance is particularly important to Canada with its wide array of climate conditions from moderate (west coast) to extremely cold (artic).