01 April 1993

This is a report on the state-of-the-art of domestic hot water heat pump technology, its applications and the existing markets in North America, Europe and Japan. Both residential and commercial building domestic hot water heat pump systems are examined including both dedicated (i.e. water heating only) and integrated (i.e. in combination with space conditioning) systems. The report concludes that the rise and fall of world oil prices in the 1980s has dictated the rise and fall of hot water heat pump sales. While hot water heat pumps have only captured a very small fraction of water heater sales in most countries, there still exist niche markets for these products either driven by regulations or incentives, or where unique climate conditions combined with high fuel prices make the technology most attractive. Such conditions exist in Sweden, the continental United States, and Hawaii. The report also highlights the “free cooling” benefit afforded by the dedicated heat pump water heater when used in commercial buildings requiring year-round cooling. When both customer and utility costs are considered (i.e. societal cost), the heat pump water heater is a lower cost choice than electric resistance water heating. The integrated space conditioning and water heating equipment developments promise improved economics compared to dedicated heat pump water heating equipment.