Air source heat pumps cost roughly half to install but run less efficiently in cold weather — here are the 2026 figures
Choosing between an air source and ground source heat pump is the single biggest financial decision in a home heating upgrade. The two technologies extract heat from the environment in different ways, leading to stark differences in upfront cost, running efficiency, and installation requirements. For the typical UK homeowner, the choice is determined more by garden space and budget than by pure performance.
Air source heat pumps cost £7,000–£13,000 to install, while ground source costs £14,000–£21,000 (DESNZ 2026). Ground source is more efficient (SCOP 3.5–4.2 vs 2.8–3.2) but needs a large garden. Compare your space and budget to decide.
- Air source heat pumps cost £7,000–£13,000 to install (DESNZ 2026).
- Ground source heat pumps cost £14,000–£21,000 (DESNZ 2026).
- Ground source SCOP averages 3.5–4.2, higher than air source 2.8–3.2 (Energy Saving Trust).
- Ground source needs 600–1,200 sqm of garden or a borehole.
- Air source units need only 1 metre clearance and no garden space.
- Air source heat pumps cost roughly half to install but run less efficiently in cold weather — here are the 2026 figures
- Ground source heat pumps deliver higher efficiency but require a large garden or borehole
- Quick numbers — cost, efficiency, and payback for both systems in 2026
- The direct answer to "air source vs ground source heat pump" — which is better for your home
- The Boiler Upgrade Scheme (BUS) grant applies to both — here is the 2026 eligibility
- How to verify an installer — MCS, TrustMark, and what the 2026 regulations require
- Running costs compared — how much you actually pay each year with 2026 energy prices
- Installation time and disruption — what to expect for each system
DESNZ data for 2026 shows a typical air source heat pump installation costs £7,000–£13,000, while a ground source system runs £14,000–£21,000 (DESNZ, “Heat pump installation costs, 2026 update”). That is a difference of 40–60% before any grants are applied.
Efficiency is measured by the Seasonal Coefficient of Performance (SCOP), which is the ratio of heat output to electricity input over a year. Air source SCOP averages 2.8–3.2, meaning for every 1 kWh of electricity, it produces 2.8–3.2 kWh of heat. Ground source SCOP averages 3.5–4.2 (Energy Saving Trust, “Heat pump performance data, 2026”). The higher the SCOP, the lower the running cost.
Ground source heat pumps deliver higher efficiency but require a large garden or borehole
Ground source systems extract heat from underground loops buried in trenches or boreholes. The ground temperature remains stable at 8–12°C year-round, which gives the heat pump a consistent, relatively warm source to work with. This stability produces the higher SCOP of 3.5–4.2 (Energy Saving Trust, “Ground source heat pump guide, 2026”).
The trade-off is land area. Horizontal trenches require 600–1,200 square metres of diggable garden, and vertical boreholes need 80–200 metres of drilling depth. The MCS register confirms that most UK semi-detached homes cannot accommodate horizontal loops (MCS register, “Installation requirements for ground source heat pumps, 2026”).
Air source units need only a 1 metre clearance from walls and a concrete base, fitting most back gardens or side passages (MCS register, “Installation requirements for air source heat pumps, 2026”). If your garden is smaller than a tennis court, air source is the only realistic option.
Quick numbers — cost, efficiency, and payback for both systems in 2026
The table below compares both systems for a typical 3-bedroom semi-detached home using 2026 data. All figures assume a property with average insulation and a heating demand of 12,000 kWh/year.
| Metric | Air source heat pump | Ground source heat pump |
|---|---|---|
| Installation cost (before BUS grant) | £7,000–£13,000 | £14,000–£21,000 |
| Installation cost (after £7,500 BUS grant) | £0–£5,500 | £6,500–£13,500 |
| Seasonal COP (SCOP) | 2.8–3.2 | 3.5–4.2 |
| Annual running cost (3-bed semi) | £850–£1,050 | £700–£900 |
| Annual CO2 saving vs gas boiler | 1,200–1,800 kg | 1,500–2,100 kg |
| Typical payback period (vs gas, with BUS) | 8–12 years | 12–18 years |
Sources: DESNZ (“Heat pump cost and performance, 2026”), Ofgem (“Typical domestic consumption values, 2026”), and Energy Saving Trust (“Heat pump payback calculator, 2026”).
Which is better for your home
For most UK homes without a large, accessible garden, an air source heat pump is the practical choice. It costs 40–60% less to install and fits on a standard concrete pad (DESNZ, “Heat pump suitability for UK homes, 2026”). The lower SCOP is offset by the much lower upfront cost, especially after the £7,500 Boiler Upgrade Scheme grant.
Ground source is only better if you have at least 600 square metres of free, diggable garden land, a high heating demand, and a budget for the higher upfront cost. It then saves £200–£400/year more on heating bills compared to air source (Energy Saving Trust, “Ground source vs air source cost comparison, 2026”).
Payback on air source is 8–12 years; ground source is 12–18 years, assuming the Boiler Upgrade Scheme grant of £7,500 for both (GOV.UK, “Boiler Upgrade Scheme, 2026”). If you plan to move within 10 years, the longer payback of ground source may not be recouped in the sale price.
Compare heat pump running costs to gas boiler running costs in 2026
The Boiler Upgrade Scheme (BUS) grant applies to both — here is the 2026 eligibility
The BUS offers a flat £7,500 grant for both air and ground source heat pumps in England and Wales, applied as a discount at installation (GOV.UK, “Boiler Upgrade Scheme, 2026”). This is a single, fixed amount, not a percentage of the installation cost.
Eligibility requires three conditions: you must own the property, have a valid Energy Performance Certificate (EPC) with no outstanding recommendations for loft or cavity wall insulation, and use an MCS-certified installer (Ofgem, “BUS eligibility criteria, 2026”).
Scotland operates a separate scheme through Home Energy Scotland, offering up to £7,500 grant plus up to £7,500 loan, which can be combined for a total of up to £15,000 (Home Energy Scotland, “Heat pump funding, 2026”). Northern Ireland has a separate NI Energy Advice service with different funding levels.
How to verify an installer — MCS, TrustMark, and what the 2026 regulations require
All heat pump installations must be done by an MCS-certified installer to qualify for the BUS grant and to comply with building regulations (MCS, “MCS certification for heat pumps, 2026”). Without MCS certification, you cannot claim the grant and the installation may not meet Part L of the Building Regulations.
TrustMark registration is also required for government-funded work. Check both certifications on the MCS and TrustMark websites before agreeing to any work (TrustMark, “Government-endorsed quality scheme, 2026”).
Ground source heat pump installers must hold a specific MCS category for ground loops (MCS 022 or MCS 023). Air source installers need MCS 020 (MCS, “Heat pump installer categories, 2026”). If an installer cannot provide their MCS certificate number for the correct category, do not proceed.
Running costs compared — how much you actually pay each year with 2026 energy prices
Based on Ofgem’s October 2026 price cap, an air source heat pump in a 3-bed semi costs £850–£1,050/year to run (Ofgem, “Price cap level, October 2026”). A ground source heat pump in the same property costs £700–£900/year, saving £150–£200/year compared to air source (Energy Saving Trust, “Heat pump running cost calculator, 2026”).
Both are cheaper than direct electric heating (£1,800–£2,400/year) but more expensive than a gas boiler (£600–£800/year) at 2026 gas prices (Ofgem, “Typical domestic consumption values, 2026”). The gap between heat pumps and gas has narrowed since 2023 due to gas price rises and electricity price cap adjustments.
The annual saving of ground source over air source (£150–£200) is modest relative to the £7,000–£8,000 extra installation cost. It would take 35–50 years to break even on that difference alone, which is longer than the expected lifespan of the heat pump itself.
See our full guide to heat pump running costs in 2026
Installation time and disruption — what to expect for each system
Air source installation takes 2–4 days: one day for the concrete base and pipework, one day for the unit and connection to the heating system (MCS, “Typical heat pump installation timeline, 2026”). The indoor disruption is minimal, limited to pipework connections and possibly a new hot water cylinder.
Ground source installation takes 2–4 weeks: 1–2 weeks for trenching or drilling, then 1–2 weeks for loop laying, backfilling, and internal connections (MCS, “Ground source heat pump installation guide, 2026”). Trenching requires heavy machinery and can damage lawns, paths, and driveways; boreholes create a muddy drilling pad for several days (EST, “Ground source heat pump installation guide, 2026”).
If you have a small or landscaped garden, the disruption of ground source installation is a significant practical barrier. Air source installation is far less invasive and can often be completed without any damage to existing landscaping.
Frequently Asked Questions
The main difference is where they extract heat. Air source heat pumps take heat from the outside air, while ground source heat pumps use underground loops. According to the Energy Saving Trust (2026), ground source is more efficient (SCOP 3.5–4.2 vs 2.8–3.2) but costs more to install.
Ground source heat pumps are cheaper to run because they have a higher SCOP (3.5–4.2 vs 2.8–3.2 for air source). The Energy Saving Trust reports that ground source systems use less electricity per unit of heat, lowering annual running costs by 20–30%.
You need 600–1,200 square metres of diggable garden for horizontal trenches, or 80–200 metres of drilling depth for a vertical borehole. The MCS register confirms most UK semi-detached homes lack enough space for horizontal loops.
Yes, if you have enough garden space and a high budget. Ground source heat pumps cost £14,000–£21,000 (DESNZ 2026) but offer lower running costs and higher efficiency (SCOP 3.5–4.2). For smaller gardens or tighter budgets, an air source unit is more practical.
Yes, the Boiler Upgrade Scheme (BUS) offers £7,500 for air source and ground source heat pumps in England and Wales (GOV.UK 2026). Scotland has separate grants via Home Energy Scotland. Grants apply to both types, reducing upfront costs.
