Here are key aspects and features of air source heat pumps

How Air Source Heat Pumps Work:

  • Heat Extraction: In heating mode, the heat pump extracts heat from the outdoor air using a refrigerant.
  • Refrigeration Cycle: The refrigerant circulates through a closed loop, absorbing heat and undergoing a phase change from a liquid to a gas.
  • Compression: The compressor increases the temperature and pressure of the refrigerant gas.
  • Heat Release: The hot refrigerant gas releases its heat inside the building through a heat exchanger.
  • Distribution: A fan or blower circulates the warm air throughout the building.
  • For cooling, the process is reversed to expel heat from indoors.

Components of an Air Source Heat Pump:

  • Outdoor Unit: Contains the compressor and the heat exchanger coil that interacts with the outdoor air.
  • Indoor Unit: Includes a heat exchanger coil that releases or absorbs heat inside the building.
  • Refrigerant Lines: Connect the indoor and outdoor units and carry the refrigerant between them.
  • Expansion Valve: Controls the flow and pressure of the refrigerant.
  • Fan or Blower: Distributes heated or cooled air throughout the building.
  • Thermostat: Controls the operation and temperature settings of the heat pump.

Efficiency and Performance

  • ASHPs are known for their energy efficiency. They move heat rather than generating it, making them more efficient than traditional heating systems.
  • Efficiency is measured by the Coefficient of Performance (COP), which compares the amount of heat delivered to the energy consumed.
Efficiency and Performance


  • Year-Round Operation: ASHPs can provide both heating and cooling, making them suitable for year-round use.
  • Environmental Impact: They produce fewer greenhouse gas emissions compared to traditional heating systems.
  • Ease of Installation: Installation is generally less complex than ground source heat pumps.
  • Cost Savings: Over time, energy savings can offset the initial installation cost.


  • Climate Suitability: ASHPs are effective in moderate climates, but their efficiency may decrease in extremely cold conditions. In such cases, supplemental heating might be needed.
  • Sizing: Proper sizing is crucial for optimal efficiency. An oversized or undersized system can lead to performance issues.
  • Noise: While modern ASHPs are designed to be relatively quiet, the outdoor unit can generate some noise during operation.


  • ASHPs are suitable for residential, commercial, and industrial applications.
  • They can be used in new constructions or retrofitted into existing buildings.

Incentives and Rebates

  • Many regions offer incentives and rebates for the installation of air source heat pumps as part of energy efficiency programs


  • Regular maintenance, such as cleaning filters and checking refrigerant levels, is essential for optimal performance.


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