Energy & Cost Impacts: Air-source Heat Pumps
The plots below show estimated cooling energy savings, heating energy savings, cooling cost savings, and heating cost savings relative to a minimum-efficiency ASHP for the ASHP product lines displayed on this website. The estimated savings ranges are shown for a variety of building types in each California climate zone. Each colored horizontal bar in the plot represents the estimated range of savings across the ASHP units that make up the given product line. The complexity of actual ASHP systems and the variety of assumptions used in modeling the estimated savings ranges means that the savings ranges displayed here should be taken as illustrative estimates only. To obtain actual estimates for your specific building, please consult an accredited mechanical contractor or engineer.
The energy use results were obtained using EnergyPlus (a US Department of Energy (DOE)-supported building energy simulation tool that is widely used for energy modeling) and DOE commercial building prototypes. Full-year, hourly-time-step simulation data were generated for sixteen California climate zones using Typical Meteorological Year (TMY3) weather data. These weather data provide a representation of median (or typical) weather. For each building type, four vintages were simulated: pre-1980, post-1980, 2004, and ASHRAE Standard 90.1-2016. The DOE commercial building prototypes were modified to use packaged heat pumps in place of packaged air conditioners. The integrated energy efficiency ration (IEER) metric was calculated for each simulated system, and the cooling energy consumption of the unit was scaled to the 2023 IEER minimum standard to represent baseline energy use in the current market. Similarly, on the heating side, the coefficient of performance (COP) metric for each simulated system was used to scale the heating energy consumption of the unit to the 2023 COP minimum standard. For each building type, the energy use by all units in the building was summed and divided by the conditioned floor area to generate an energy use intensity in kWh/sq-ft. These data were summed to get cooling and heating energy use for each building for the summer and winter months (with summer months defined as May through September and winter months defined as October through April). Cooling and heating energy savings for each ASHP unit and building were estimated based on these values. The energy savings for each building vintage were then averaged using building vintage weights developed from the Energy Information Agency Commercial Building Energy Consumption Survey (CBECS). Finally, the cost savings estimates were calculated by multiplying the summer and winter energy savings by the summer and winter energy prices for California, respectively, and then adding the resulting seasonal cost savings together.
