Air source vs ground source heat pump
Choosing the right heat pump for your home is an important decision. So, let's break down the differences between air source and ground source heat pumps, so you can find the perfect fit for your home. Whether you’re into quick and easy installations or you’re ready to dig deeper (literally), we’ve got you covered.
Air source or ground source? What's the difference?
Both air source and ground source heat pumps work the same magic: they harness natural energy from their surroundings, and bring it into your home. The main difference is where they find that heat.
Air source heat pumps (ASHPs).
These clever devices pull heat from the air outside, even when it feels chilly to us. They're like high-tech fridges in reverse, sitting outside your home and transferring heat from the air into your home, constantly working to keep your home comfortable.
Ground source heat pumps (GSHPs).
These dig a bit deeper, extracting heat from the ground below. They need a network of pipes buried in your garden to collect heat from the soil. The temperature underground is more stable, so GSHPs can be super-efficient, even in the coldest winter months.
Air source v ground source, the physical differences.
ASHP.
A compact unit that sits outside your home, similar to an air conditioning unit. It's connected to your heating system indoors.
GSHP.
These also operate outside, but require more space as they need ground loops (pipes buried in your garden) or boreholes (pipes drilled vertically).
Efficiency.
When it comes to efficiency, ground source heat pumps generally take the lead. They can be up to 50% more efficient than air source pumps because the ground maintains a relatively constant temperature year-round. However, ASHPs are still highly efficient, especially in milder climates.
Upfront, installation and running costs.
Air source heat pumps.
Upfront cost: £7,000 - £13,000
Installation cost: Included in the price, air source heat pump installation is fairly straightforward and minimal disruption to your home.
Running cost: Lower than traditional systems, like old boilers and LPG, but depends on electricity prices. Read more on heat pump running costs.
Ground source heat pumps.
Upfront cost: £10,000 - £18,000
Installation cost: Higher due to groundworks, possible interruption to patio or decking area depending on location.
Running cost: Lower, due to higher efficiency.
Government grant / boiler upgrade scheme.
Great news! Both types of heat pumps are eligible for government grants, like the Boiler Upgrade Scheme.¹ Check out our heat pump grant page for more details on how you can save on the cost of installation.
2 The Government’s Boiler Upgrade Scheme is valid for heat pumps that are commissioned from 1 April 2022. To be eligible for the grant, a valid Energy Performance Certificate (EPC) from the last 10 years. Unfortunately new build homes are ineligible for the Boiler Upgrade Scheme. Owner and property eligibility apply. To see the full eligibility criteria and exclusions, visit the Government Boiler Upgrade Scheme website.
Installation and planning permission.
An ASHP installation is relatively straightforward, much easier and quicker, and typically takes a few days. They usually don’t require planning permission unless you live in a listed building or conservation area.
GSHPs are a bit more complex, and take longer to install because of the groundwork needed. You might even need planning permission, especially for the ground loops.
Space and location.
ASHPs: Ideal for homes with limited outdoor space, as they only need a small area for the unit.
GSHPs: Require a decent amount of outdoor space for ground loops and/or boreholes. Therefore they might not be right for all properties.
Lifespan.
Both ASHPs and GSHPs are built to last, with lifespans of around 15-20 years for ASHPs and up to 25 years for GSHPs, given proper maintenance.
Sustainability.
Both ASHPs and GSHPs are environmentally friendly alternatives to traditional heating systems, especially when powered by renewable electricity. In a head-to-head, we’d say GSHPs just take the lead in sustainability due to their higher efficiency and longer lifespan. But, they do cost more and are trickier to install.
What are the benefits and disadvantages of air source heat pumps?
Benefits of air source heat pumps.
Easier installation. Quicker and less disruptive to install.
Lower upfront cost. Generally cheaper than ground source.
Space saving. Doesn’t require large garden space.
Disadvantages of air source heat pumps.
Efficiency. Slightly less efficient than ground source.
Noise. Can produce some noise, though modern models are pretty quiet.
Weather dependent. Efficiency can drop in very cold weather.
What are the benefits and disadvantages of ground source heat pumps?
Benefits of ground source heat pumps.
Higher efficiency. Consistent heat from the ground.
Lower running costs. More efficient, hence cheaper to run.
Silent operation. No external units, so they’re super quiet.
Disadvantages of ground source heat pumps.
Higher upfront cost. More expensive due to groundworks.
Complex installation. Requires a lot of space and time.
Planning permission. May be needed, adding to the hassle.
Which type of heat pump is best for your home?
It’s a tough choice, we know! The best heat pump for you depends on several factors, including:
Your budget. How much are you willing to invest upfront?
Your home. Do you have enough outdoor space for a GSHP?
Your priorities. Are you more focused on low running costs or lower upfront costs?
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