Glossary
What Is an Air Source Heat Pump? Plain-English Guide (2026)
Definition: A heat pump that extracts heat from outdoor air and transfers it inside your home
Air Source Heat Pump Explained
An air source heat pump (ASHP) works like a fridge in reverse – it extracts heat from outdoor air even at temperatures as low as -20°C. ASHPs are cheaper to install than ground source (£7000-a government energy efficiency grant amount0) and qualify for up to £7,500 in government grants.
How Does a Air Source Heat Pump Work?
- Fan draws outside air over an evaporator coil containing refrigerant
- Refrigerant absorbs heat and evaporates to gas
- Compressor increases gas pressure and temperature
- Hot gas passes through condenser releasing heat to home's water circuit
Pros and Cons of a Air Source Heat Pump
| Pros | Cons |
|---|---|
| Lower install cost than ground source (£7000-a government energy efficiency grant amount0) | Less efficient than ground source in very cold weather |
| No garden excavation needed | Outdoor unit produces some noise |
| Qualifies for government grant (currently up to £7,500, subject to eligibility) | Requires adequate outdoor wall or ground space |
| Can provide heating and hot water year-round | Best paired with underfloor heating or oversized radiators |
Frequently Asked Questions
What is an Air Source Heat Pump?
A heat pump that extracts heat from outdoor air and transfers it inside your home
How does an Air Source Heat Pump work?
An air source heat pump (ASHP) works like a fridge in reverse – it extracts heat from outdoor air even at temperatures as low as -20°C. ASHPs are cheaper to install than ground source (£7000-a government energy efficiency grant amount0) and qualify for up to £7,500 in government grants.
Why is an Air Source Heat Pump important for homeowners?
Understanding air source heat pump helps you make informed decisions about energy improvements to your home and may affect the grants, savings and payback periods available to you.
Is an Air Source Heat Pump relevant to home energy improvements?
Yes — air source heat pump is a key concept in home energy improvements. It may affect system sizing, efficiency and eligibility for government grants and incentives.
Where can I learn more about air source heat pump?
You can find more information on renewable energy terminology and policy by searching online or consulting with a qualified installer in your area.