How Much Does an Air Source Heat Pump Cost in 2026? (UK)
An air source heat pump (ASHP) in 2026 UK costs £7,500–£14,000 fully installed for a typical 3-bed home, after the £7,500 Boiler Upgrade Scheme (BUS) grant. Headline price before grant is £15,000–£21,500. At a real-world SCOP of 3.5 on a 2026 unit cost of 24p/kWh electricity, running cost is broadly on par with a 90% efficient gas boiler — not the dramatic saving some installers promise.
2026 ASHP installed cost by property size
- 1–2 bed flat (6 kW unit): £11,000–£14,500 (£3,500–£7,000 after grant)
- 2–3 bed semi (8 kW): £14,500–£17,500 (£7,000–£10,000 after grant)
- 3–4 bed detached (10 kW): £16,000–£19,500 (£8,500–£12,000 after grant)
- 4–5 bed / poorly insulated (12–14 kW): £18,000–£21,500 (£10,500–£14,000 after grant)
- Hot water cylinder upgrade (mandatory in most cases): £1,400–£2,800 included above
- Radiator upsizing (if required): £200–£380 each
Running cost vs a modern gas boiler (2026)
The honest 2026 maths on a typical 12,000 kWh/year heat demand:
- Gas combi 90%: 12,000 / 0.9 = 13,333 kWh gas at 7.5p = £1,000/yr
- ASHP SCOP 3.0 (poor design): 12,000 / 3.0 = 4,000 kWh elec at 24p = £960/yr
- ASHP SCOP 3.5 (good design): 12,000 / 3.5 = 3,429 kWh elec at 24p = £823/yr
- ASHP SCOP 4.0 (excellent design + low-flow rads): 12,000 / 4.0 = 3,000 kWh elec at 24p = £720/yr
SCOP (Seasonal Coefficient Of Performance) is the lever. Quotes that just promise “a SCOP of 4.5” without an MCS Performance Estimate (MCS PE) are marketing. Always insist on the PE document.
What the £7,500 BUS grant covers
Boiler Upgrade Scheme grant (England & Wales) is £7,500 off an MCS-certified ASHP installation, paid direct to the installer who deducts it from your quote. You don’t apply yourself — the installer does. Eligibility:
- Property has an EPC with no outstanding loft / cavity insulation recommendations (or you fix them first)
- Existing system is a fossil fuel boiler (gas, oil, LPG) or electric storage heaters
- Property is in England or Wales (Scotland uses Home Energy Scotland up to £15,000)
Hidden cost lines to ask about
- Larger radiators: ASHPs run at lower flow temps (35–50°C), so undersized rads will struggle. A reputable installer will model every room.
- Acoustic mounting: Permitted Development limits noise to 42 dB at the neighbouring property; expect £200–£400 for proper mounts.
- Electrical upgrade: Some older single-phase supplies need a service-head upgrade or load monitor; £0–£800 depending on DNO.
- Time-of-use tariff onboarding: Cosy / Agile-style tariffs add 10–25% to real-world savings but require a smart meter.
Red flags in 2026 ASHP quotes
- No MCS Performance Estimate provided — walk away
- SCOP claimed above 4.5 without underfloor heating — physically very rare
- Installer not on the MCS public register (without it the BUS grant is invalid)
- Unit oversized “to be safe” — over-sized ASHPs short-cycle and run worse
- No room-by-room heat loss survey — a single “whole house” figure is not compliant
FAQs
Related guides
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