Small Medium Business HPWH Emergency Deployments

Small- and medium-sized businesses (SMBs) often replace failed water heaters with gas equipment because electric alternatives can require panel upgrades, added wiring, and longer installation timelines. 120 V plug-in heat pump water heaters (HPWHs) could offer a simpler emergency replacement pathway that supports building decarbonization, but little field data exists on whether they can meet SMB hot water needs in practice. This study evaluated whether 120 V plug-in HPWHs are a viable option for SMB applications with modest domestic hot water demand. The work focused on three questions: (1) what hot water draw profiles are typical in SMBs, (2) whether 120 V HPWHs can meet those loads, especially in emergency replacement situations, and (3) how customers and contractors experience installation and operation. The project team installed and monitored 120 V HPWHs at five SMB sites: a shopping center, small office, warehouse, nonprofit social service agency, and religious organization with preschool functions. Field metering captured hot water draws, electrical energy use, and water temperatures, and the team used these data to estimate daily usage, coefficient of performance (COP), baseline energy use, and operating costs. Results showed that all five sites used much less hot water than traditional sizing methods would predict, and 120 V HPWHs were adequate from a capacity standpoint at every site. However, low and intermittent demand reduced efficiency: at the warehouse, office, and nonprofit sites, COP was often below 1 on low-use days, while the religious organization achieved weekday COP above 3.0 but lower weekend performance. The findings suggest that 120 V HPWHs are viable for a targeted subset of SMBs with modest but meaningful loads and compact plumbing layouts, while very low-use or dispersed-fixture sites may be better served by point-of-use electric resistance or hybrid approaches.