Air-to-Air Heat Pump
It has mainly been employed in moderate climates for air conditioning applications, however recent technological advancements allow for their efficient use in colder climates. This has recently led to relatively high interest for air-to-air heat pumps in Norway and Finland. Air-source heat pumps are significantly cheaper and easier to install than ground-source alternatives and there is no need for permission from local authorities for their installation. However, they perform significantly worse in terms of efficiency. COP = 3–3.5