TA-23-C023 – Decarbonization through Residential Air-Source Heat Pumps PDF

This paper’s objective is to present an overview of testing and energy conservation standards regulations in the U.S. for single-phase heat pumps with a cooling capacity of less than 65,000 Btu/h, and how such provisions can be further revised to alleviate possible barriers to heat pumps being viewed as viable heating and cooling solutions in jurisdictions endeavoring to meet net zero energy and decarbonization goals. Although new federal provisions for heat pumps will be implemented starting January 1, 2023, and are expected to yield metrics that are more representative of the average use cycle of a covered product installed in the field, opportunities continue to exist on improving the performance metrics for heat pumps installed in a variety of regions with specific sizing needs based on climate zones. The paper will suggest multiple pathways to explore for the sake of improving the representativeness of performance metrics, including but not limited to the incorporation of a controls verification procedure into the test procedure, test procedure revisions to address heating mode tests in lower ambient outdoor temperatures that are repeatable and reproducible in laboratory environments, updated fractional bin hours for cooling and heating, impacts of refrigerant transition on performance ratings, and accounting of fan energy consumption for air handlers and energy consumption of crankcase heaters in certain outdoor ambient conditions.

Heat pumps are currently subject to national standards at the federal level. The paper will explore possible pathways towards regional standards for such products and how building standards have been revised in recent years to facilitate heat pump adoption. Additional recommendations will be made in this paper on issues pertaining to demand response in cooling and heating modes, approaches to minimize auxiliary heating, use of standardized diagnostic codes to facilitate quality installations, and standardized reporting of expanded ratings.