With rising energy costs and a growing focus on sustainability, many homeowners are turning to air source heat pumps (ASHPs) as a cost-effective and environmentally friendly way to heat and cool their homes. But how exactly does an air source heat pump work?

The Basics of an Air Source Heat Pump

An air source heat pump is a device that transfers heat from the outside air into your home in the winter. Unlike traditional heating systems that generate heat by burning fuel, ASHPs simply move heat, making them highly efficient.

Key Components of an ASHP

An air source heat pump consists of several key components that work together to extract and distribute heat:

  • Outdoor Unit: Contains a fan and a heat exchanger that absorbs heat from the outside air.
  • Refrigerant: A special fluid that circulates through the system, absorbing and releasing heat as it changes from a liquid to a gas and back again.
  • Compressor: Increases the pressure and temperature of the refrigerant, enhancing heat transfer.
  • Indoor Unit: Distributes the heated or cooled air throughout your home via a fan or central duct system.
  • Expansion Valve: Regulates the flow of refrigerant and helps control the system’s efficiency.

How an ASHP Heats Your Home

Even in cold temperatures, there is heat energy in the outdoor air even at minus 20 degrees and modern heat pumps can now function at this temperature. The outdoor unit extracts this heat and transfers it to the refrigerant. The compressor increases the refrigerant’s pressure and temperature. The heated refrigerant passes through the indoor coil, releasing heat into your home. The refrigerant then cools and returns to the outdoor unit to repeat the cycle.

Benefits of an Air Source Heat Pump

  • Energy Efficiency: ASHPs can be up to four times more efficient than traditional heating systems and with the grid being decarbonised it will continue to reduce your carbon footprint.
  • Lower Carbon Footprint: They use electricity instead of burning fossil fuels, reducing emissions. 
  • Year-Round Comfort: Providing you with a consistent comfortable heat all year-round so no more putting your thermostat up and down.
  • Cost Savings: Reduced energy usage leads to lower utility bills over time.
  • Longevity: A well-maintained ASHP can last 15–20 years.

Read more here.

Air source or Ground source – which is right for your home?

Read our blog about which heat pump is right for your home here.