Air source heat pumps advantages and disadvantages, insulation and weather

Air-Source Heat Pumps

Air source and ground-source heat pumps

Air source heat pumps are different from water and ground heat pumps. Instead of extracting the heat or coldness from ground or water, they extract them from the outdoor air.

Image: Air-Source Heat Pumps Scheme, courtesy of Danfoss

Central air-source heat pumps

Most heat pumps are two-piece units. They involve:

1 - An outdoor unit - looking like an air conditioner in size and appearance - usually consisting of an outdoor coil, a compressor, a reversing valve and a fan.

2 - An indoor unit, called an air handler, that looks like a gas furnace (though the system doesn't work or involve any furnace). The air handler contains a large blower and a filter just like conventional air conditioners.

In the case of central heat pumps the heated (or cooled) air is distributed around the house via ductwork (and the blower).

Ductless mini split heat pumps

In ductless heat pump systems there is only one outdoor unit and multiple indoor units. The term "mini" associated to these pumps describe the small indoor units located in each room or part of the house (articulated with the outdoor unit through a conduit system) where the final heated or cooled air is produced and blown.

For more details, see: Ductless mini split heat pumps.

Supplemental heater

A supplemental heater is used to surpass the system limitations during freezing times (below 30ºF - 0ºC), when the heat pump can't replace all heat losses.... In this case, electric heating elements in the indoor unit may turn on automatically to make up the difference.

Advantages of air heat pumps

Air heat pumps are emerging as a popular choice due to their simple ‘plug and play’ installation and competitive pricing. Air heat pumps are typically competitive with traditional electrical and fuel-based systems, though not with gas-powered appliances (see: Are Heat Pumps Suitable for my home).

See: Heat Pumps prices

Disadvantages of air-source heat pumps

Air source heat pumps perform much better in mild temperate. In climates with extended periods of freezing temperatures, air-source heat pumps have large limitations, compelling users to use electric or gas heaters...

Ground source heat pumps are more efficient, and may overcome this limitation of air-source heat pumps.