Impacts of Flexible Demand Events by Residential Heat Pump Water Heaters in San Joaquin Valley

This report presents a field evaluation of flexible demand events with heat pump water heaters (HPWHs) operating in 10 occupied single‑family homes in the San Joaquin Valley. The study examined HPWH responses to California Energy Commission’s Title 24, Joint Appendix 13 defined “light shed” and “deep shed” flexible demand events. The evaluation focused on documenting observed load response behavior, customer service impacts, and operational characteristics relevant to utility programs and emerging expectations around appliance‑level load management. The study’s primary purpose is empirical: to characterize actual field performance and identify practical considerations associated with HPWH demand management. The study looked at two HPWH models and found modest bill savings for one model. Other findings have implications for the California Energy Commission’s ongoing consideration of flexible demand appliance standards under Senate Bill 49.