Heat Pump Costs in Cornwall: A Complete 2026 Breakdown

Before we get into the variables, here is the honest, real-world price band you can expect from CCS for a complete air source heat pump installation in Cornwall in May 2026:

• Small property (1-2 bed flat or terrace): £14,500-16,500 pre-grant, £7,000-9,000 after BUS grant
• Mid-size (3-bed semi or terrace): £16,500-19,500 pre-grant, £9,000-12,000 after BUS
• Large (4-5 bed detached): £19,500-23,500 pre-grant, £12,000-16,000 after BUS
• Rural/farmhouse (5+ bed, oil-replacement): £22,000-28,500 pre-grant, £14,500-21,000 after BUS

These figures include the heat pump, hot water cylinder, controls, all pipework, electrical works, MCS commissioning, and the £7,500 Boiler Upgrade Scheme grant pre-deducted. They exclude radiator upgrades (sometimes needed, sometimes not) and any major fabric upgrades like loft insulation top-up.

For ground source, add roughly £8,000-15,000 to the equivalent ASHP figure depending on whether trenches or boreholes are used. See our Cornwall GSHP guide for the full breakdown.

The big picture: in 2022 we were quoting £18,000-22,000 net for a typical 4-bed install. In May 2026, with hardware costs down and the grant raised to £7,500, that same job is around £11,000 net. Heat pumps have never been cheaper in real terms.

The two heat pump families have very different cost structures. Air source is around 90% of the Cornwall market because it is cheaper, faster and works on virtually any property. Ground source is more expensive upfront but cheaper to run and ideal for rural properties with land.

Air source (ASHP)

• Heat pump unit: £3,500-7,500 (4-16kW range, e.g. Vaillant aroTHERM plus, Daikin Altherma 3 R, Mitsubishi Ecodan)
• Hot water cylinder: £900-1,800 (180-300L unvented, e.g. Telford Tempest or Mixergy iHP)
• Buffer/volumiser if needed: £200-450
• Pipework, fittings, valves: £400-700
• Electrical works (consumer unit upgrade, isolator, supply cable): £350-900
• Labour (3-5 days for a typical install): £2,400-4,000
• MCS commissioning, certification, building notification: £350-500

Typical ASHP total: £8,100-15,850 net of £7,500 BUS grant

Ground source (GSHP)

Same components as ASHP plus:

• Ground loops or boreholes: £6,000-22,000 (depending on horizontal trenches, slinky coils, or vertical boreholes)
• Glycol-water charge and circulation pump: £600-1,200
• Manifold and brine controls: £450-900
• Excavation/groundworks contractor: £2,500-8,000
• The GSHP unit itself is typically £1,000-2,500 more than equivalent ASHP

Typical GSHP total: £18,000-32,000 net of £7,500 BUS grant.

For most Cornwall townhouses and standard semis, ASHP is the right choice. For rural farmsteads with paddock land and a 200+m² floor area, GSHP's 30% efficiency advantage often justifies the higher capital. See our heat pump installation page or the Cornwall GSHP pillar guide.

Heat pump cost scales primarily with kW size, which scales with property heat loss, which depends on age, fabric, glazing and floor area. Here is what we are charging in Cornwall for typical property archetypes — all figures are net of the £7,500 BUS grant and assume an air source heat pump with a new hot water cylinder.

Two patterns to notice. First, property age matters more than floor area. A 1900s 4-bed farmhouse has higher heat loss than a 1990s 4-bed semi at the same floor area, requiring a larger heat pump and often more radiator upgrades. Second, new-builds are cheaper because heat loss is low, no fabric upgrades are needed, and the install slots into an existing low-temperature system.

To get an accurate quote for your specific property, we conduct a free MCS-compliant heat loss survey. Call 01209 596 002 or visit our heat pump page.

If you want a quick mental model, work in pounds per kilowatt of heat pump capacity. Here is what the Cornwall market looks like in May 2026, all-in installed cost before the BUS grant:

Worked example: a 4-bed Truro semi with a heat loss of 8.4kW and well-sized 1990s radiators sits at the simpler end of the ASHP retrofit range. 8.4kW × £2,150/kW = £18,060 gross, less the £7,500 BUS grant = £10,560 net. That is squarely within our typical 4-bed range above.

Where it goes wrong: if the heat loss survey reveals undersized radiators throughout, add £150-300 per radiator upgrade. A typical 4-bed needs 6-9 radiators upgraded, adding £1,200-2,700 to the project. We always quote this transparently as a separate line so you can budget properly.

The £7,500 grant is generous but it does not always cover everything. Here are the cost lines that catch homeowners by surprise:

Radiator upgrades (£800-3,500)

Heat pumps deliver lower flow temperatures (35-55°C versus 70-80°C for a boiler). Existing radiators sized for boiler flow temps may need upgrading. In our Cornwall surveys, roughly 60% of homes need 1-3 radiators uprated, 25% need a full house upgrade, and 15% need none. Type 22 double-panel doubles or Type 21 K2 are typical replacements at £150-300 fitted each.

Hot water cylinder (£900-1,800)

Most boiler combi conversions need a brand new unvented cylinder because there is no existing one. In a system-boiler home, the existing cylinder is usually too small (120L is common) and needs replacing with 200-300L for heat pump use. CCS includes the cylinder in our standard quotes — but check carefully if comparing competitor quotes.

Electrical works (£350-1,200)

The heat pump needs a dedicated 32A or 40A supply from the consumer unit, often requiring a consumer unit upgrade if your current one is 17th edition or earlier. Add £600-900 for a full CU swap if needed.

Planning and listed building (£0-1,500)

Most ASHP installs in Cornwall are permitted development. Conservation areas, AONBs and listed buildings need a planning application (£258 fee plus our drawing/statement work, usually £400-1,000).

Removal of old system (£200-800)

Decommissioning an old oil tank, gas boiler, or solid fuel system. Oil tank removal is the costliest because of the contamination potential and disposal fees.

Building works (£0-3,000)

Hard-paving for the heat pump base, increased pipework boxing, occasional minor wall builds. Most installs are zero or minimal here, but rural properties sometimes need £1,500+ of stand-out groundworks.

Total potential extras: £0-7,000, with most properties landing in the £500-2,500 range. We itemise everything in our quotes — no surprises after sign-off.

The Ofgem Q1 2026 price cap sets the headline numbers we work with:

• Electricity: 24.67p/kWh, daily standing charge ~64p
• Mains gas: 5.74p/kWh, daily standing charge ~32p

For a heat pump running at SCOP 3.5 (typical for a well-designed system on existing radiators), every 1kWh of heat costs 24.67 ÷ 3.5 = 7.05p. At SCOP 4.0 (with weather compensation, low-temp emitters), it drops to 6.17p/kWh of heat.

Compare to fuel costs delivered as heat (assuming boiler efficiency 90%):

• Mains gas heat at 90% boiler: 5.74 ÷ 0.90 = 6.38p/kWh of heat
• Heating oil (78p/litre, 10.4kWh/litre, 88% efficiency) = 8.52p/kWh of heat
• LPG (75p/litre, 7.1kWh/litre, 90% efficiency): 11.74p/kWh of heat

So a SCOP 3.5 ASHP on standard tariff is roughly on par with mains gas, beats oil by ~17%, and beats LPG by 40%+. On a smart tariff like Octopus Cosy (effective rate around 18-20p/kWh for heat pump load), running costs drop another 15-25%, taking effective heat cost to around 5.0-5.7p/kWh — comfortably the cheapest option.

Annual running cost examples (Cornwall, May 2026)

Add a smart tariff and the ASHP column drops by a further 15-20%. See our heat pump vs gas pillar guide for the deeper comparison.

For Cornwall specifically, the fuel mix matters because around 35-40% of properties are off mains gas. The economic case for a heat pump is strongest where you are replacing oil or LPG.

Replacing oil — the strongest case

Oil prices have been volatile but the trend is upward as carbon levies bite. A 4-bed Cornwall farmhouse burning 2,500L of oil per year costs around £1,950 today; that same heat from an ASHP at SCOP 3.5 costs around £1,375 — a saving of £575/year. Add the £7,500 BUS grant (oil customers qualify) and payback is typically 8-11 years. Oil boilers also face uncertain regulatory futures; banning oil heating in off-gas-grid homes from 2026 was deferred but remains on the policy agenda.

Replacing LPG — almost always wins

LPG is the most expensive mainstream fuel in the UK. A typical 4-bed using 1,800L of LPG annually pays around £1,350 in fuel; the heat pump equivalent is £1,375, but the LPG figure does not include the standing charge of the bulk tank rental and the higher boiler servicing costs. Net-net, heat pumps almost always win against LPG, with payback often inside 6 years post-grant.

Replacing mains gas — the marginal case

Modern mains gas at 5.74p/kWh is genuinely cheap. A heat pump at SCOP 3.5 produces heat at roughly the same cost (7.05p versus 6.38p including boiler efficiency). The case for switching from a working modern combi to a heat pump is mostly carbon and future-proofing, not cash savings. However: if your gas boiler is 12+ years old and approaching replacement anyway, a heat pump comes out ahead because the £7,500 grant offsets the higher capital cost. See our heat pump vs gas pillar guide.

Payback depends on what you are replacing and your tariff. Here are typical Cornwall figures for a 4-bed detached, post-grant:

Two important caveats. First, these calculations assume current (May 2026) tariffs. Electricity is widely expected to decarbonise faster than gas, with grid carbon intensity falling by ~5%/year and electricity unit rates likely to fall relative to gas through the late 2020s as zonal pricing and abundant renewables drive merit-order shifts. Second, payback ignores the capital value uplift on your property: an ASHP install raises EPC by 1-2 bands, and properties EPC C+ trade at a 2-4% premium to EPC D-G in Cornwall (per Land Registry data analysis 2024-2026).

For most Cornwall heat pump customers, payback is real but slow. The bigger drivers are EPC compliance for landlords, future fuel cost insurance, and the carbon reduction. We are happy to model your specific scenario — call 01209 596 002 or see our finance options page for 0% APR funding via our partner Phoenix Financial Services.