Air Source Heat Pumps in Southeast Alaska
Air source heat pumps (ASHP) are heating appliances that act like a refrigerator in reverse. Whereas a refrigerator removes heated air from the interior and transfers it to the room, an air source heat pump extracts heat from the air outside a house and transfers it to a room. Even in cold climates, “cold” outdoor air still contains heat. An ASHP uses electricity to “step up” that heat to a temperature warm enough for space heating. Until recently, ASHPs have been used in areas that only experienced mild winters, but more recent models can work in colder climates.
Southeast Alaska is a good candidate for ASHP heating appliances because of its milder climate and access to affordable hydroelectric power. Because ASHPs use less electricity than electric resistance heating appliances, they could reduce heating costs for homeowners using such systems. However, there is still uncertainty about the performance of ASHPs in cold climates -- including defrost mechanisms for the coldest days of the year.
CCHRC conducted a study of ASHPs in Southeast Alaska during the winter of 2014-2015 to learn more about their performace and limitations in Alaska's climate. In 2014, data logging systems were installed on three ASHPs to measure their electrical use and energy output. Researchers also surveyed the electrical use of 30 systems in Southeast communities.
The final report is available here.
For additional background on ASHPs in Southeast Alaska, check out this technology assessment, which includes a literature review, interviews with installers, distributers, and ASHP owners, an inventory of existing ASHPs in Alaska, and models of the cost and heating capacity of heat pumps.