RESIDENTIAL HEAT PUMP WATER HEATER (HPWH) DEVELOPMENT STATUS—USA
Heat pump water heaters (HPWH) have the potential to reduce annual water heating costs for residential and commercial buildings by a factor of 2 or more compared to conventional electric resistance water heating products. This paper summarizes the current state of HPWH development in the United States including design evolution, laboratory performance, field performance, and accelerated life test results. Also discussed are consumer perceptions of current products and an assessment of factors impacting market acceptance of HPWHs. The laboratory and field studies indicate that the technology has progressed considerably with fairly reliable and highly efficient products becoming available. However, market penetration remains small, primarily due to high initial COSTs.