A Comprehensive Guide to Air Source Heat Pumps and why it will be beneficial to have a system installed.

Air Source Heat Pumps (ASHPs) are becoming increasingly popular in the United Kingdom as a sustainable and efficient way to heat homes. With rising energy costs and environmental concerns, ASHPs offer a cost-effective and eco-friendly alternative to traditional heating systems. This information document provides an in-depth overview of ASHPs, covering their benefits, how they work, what they are, and the government schemes supporting their adoption.
What Are Air Source Heat Pumps?
Air Source Heat Pumps (ASHPs) are renewable heating systems that extract heat from the outdoor air and use it to provide heating and hot water for homes. They work on the principle of heat transfer and can operate in temperatures as low as -15°C. ASHPs consist of two main components: an outdoor unit (the evaporator) and an indoor unit (the condenser). The evaporator absorbs heat from the air, while the condenser releases the heat into your home’s heating system.
ASHPs come in two main types:
Air-to-Water ASHPs: These ASHPs transfer heat to a water-based central heating system, including radiators, underfloor heating, and hot water tanks.
Air-to-Air ASHPs: These ASHPs distribute heat directly into the living space using fans, functioning similarly to air conditioning units but in reverse.
How Air Source Heat Pumps Work
ASHPs operate on the same fundamental principles as a refrigerator, but in reverse. They absorb heat from the outside air and release it inside to heat your home. The key components and steps in the process are as follows:
- Evaporator Coil: The outdoor unit contains an evaporator coil filled with a refrigerant. This coil is exposed to the outside air, where it absorbs heat even in cold temperatures
- Refrigeration Cycle: The refrigerant, typically a fluid with a low boiling point, circulates through the system. As it passes through the evaporator coil, it evaporates, absorbing heat from the air.
- Compressor: The gaseous refrigerant is then compressed by a compressor, which increases its temperature and pressure.
- Condenser Coil: The high-temperature, high-pressure refrigerant is then passed through a condenser coil in the indoor unit. This coil releases the absorbed heat into the home's heating system.
- Distribution: The heat can be distributed either via radiators, underfloor heating, or fans to warm the living space or water in a storage tank for domestic hot water.
- Repeating Cycle: The refrigerant returns to the evaporator, and the cycle continues.
The key advantage of ASHPs is their ability to extract heat from the air even in colder conditions, making them suitable for the UK climate.
Benefits of Air Source Heat Pumps
ASHPs offer numerous advantages, making them an attractive option for homeowners. Some of the key benefits include:
Energy Efficiency: ASHPs are highly energy-efficient and can provide up to three units of heat for every unit of electricity they consume. This means lower energy bills and reduced carbon emissions.
Environmentally Friendly: ASHPs are a greener heating solution. They generate heat by harnessing renewable energy from the air, reducing your carbon footprint and helping combat climate change.
Lower Operating Costs: ASHPs are known for their cost-effectiveness. With lower energy consumption and reduced maintenance compared to traditional heating systems, they can lead to significant long-term savings.
Reliable in All Seasons: ASHPs can operate efficiently even in cold weather. This reliability ensures that your home remains warm throughout the year.
Reduced Carbon Emissions: By reducing the reliance on fossil fuels for heating, ASHPs help to lower carbon emissions, contributing to a cleaner and more sustainable environment.
Eligibility for Government Incentives: The UK government has introduced various schemes to encourage the adoption of ASHPs, including the Renewable Heat Incentive (RHI) and the Green Homes Grant. These incentives can provide financial support to homeowners who install ASHPs.
Low Maintenance: ASHPs require minimal maintenance compared to traditional heating systems, which often involve the servicing of boilers. This translates to lower maintenance costs over time.
Heating and Cooling: Air-to-Air ASHPs can both heat and cool your living space, offering year-round comfort in all weather conditions.
Space Saving: ASHPs are compact and do not require a fuel storage tank, freeing up space in your home.
Government Schemes and Support
The UK government is committed to promoting the adoption of renewable heating technologies, including ASHPs. Various schemes and incentives are available to assist homeowners in the transition to more sustainable heating solutions.
Renewable Heat Incentive (RHI) –
The Renewable Heat Incentive is a government scheme designed to encourage the installation of renewable heating systems like ASHPs. Under this scheme, homeowners receive financial incentives for using renewable energy sources to heat their homes. The RHI provides quarterly payments for seven years, making ASHPs an even more attractive option for homeowners.
Green Homes Grant – The Green Homes Grant is a government initiative aimed at improving the energy efficiency of homes. While not exclusively for ASHPs, the grant can be used to partially fund the installation of energy-efficient heating systems, including ASHPs. The grant provides funding for up to two-thirds of the cost of eligible home improvements, making it a valuable option for homeowners looking to upgrade their heating systems.
Energy Company Obligation (ECO) – The Energy Company Obligation is an energy efficiency scheme that obliges energy suppliers to help improve the energy efficiency of homes, including the installation of ASHPs. Low-income and vulnerable households may be eligible for assistance with the installation costs through this scheme.
Conclusion
Air Source Heat Pumps are a sustainable and efficient heating solution that offer numerous benefits to homeowners in the UK. They harness renewable energy from the outdoor air, reduce energy bills, and help lower carbon emissions. With government support in the form of incentives like the Renewable Heat Incentive and the Green Homes Grant, the adoption of ASHPs is becoming increasingly accessible to homeowners. If you’re looking for a greener, more cost-effective way to heat your home, ASHPs are an excellent choice that combines eco-friendliness and long-term savings.