Replacing Your Oil Boiler with a Heat Pump in Cornwall
Replacing an oil boiler with a heat pump in Cornwall? Until March 2027 the Boiler Upgrade Scheme pays £9,000 where a home heated by oil has no mains gas connection. Here is what the switch involves, what it costs and how the grant works.
Why Cornwall Oil Boiler Owners Should Consider Switching Now
Around 40,000 Cornwall homes use oil for central heating — approximately 15.36% of Cornwall properties, compared to just 3.35% for England as a whole. Where an oil-heated home has no mains gas connection, the Boiler Upgrade Scheme (BUS) pays £9,000 towards an air source heat pump until March 2027, subject to the scheme's eligibility conditions — £1,500 more than the standard £7,500. With oil prices volatile, that uplift makes the case for switching stronger now than it will be after March 2027.
The Boiler Upgrade Scheme Grant for Oil-Heated Homes
The BUS grant pays £9,000 towards your heat pump installation cost until March 2027 if you are replacing oil or LPG and have no mains gas connection (£7,500 otherwise). You do not pay it and claim it back — as your MCS certified installer, we apply to Ofgem on your behalf, receive the voucher, and deduct it directly from your invoice. You only ever pay the balance.
Eligibility is straightforward for oil boiler owners:
- You own the property (homeowners and landlords both qualify)
- You have a valid Energy Performance Certificate (EPC) — no minimum rating required
- You are replacing an oil boiler with a heat pump
- The property is in England or Wales
- The installer is MCS certified (CCS Heating & Renewables holds full MCS certification)
With a typical installation costing £10,000–£14,000, the £9,000 grant for an oil-heated home with no mains gas brings the cost to £1,000–£5,000 (£2,500–£6,500 at the standard £7,500). See our full grants guide.
Running Cost Comparison: Oil vs Heat Pump
Based on Ofgem Q2 2026 energy prices:
| System | Efficiency | Fuel cost | Cost per kWh heat |
|---|---|---|---|
| ASHP (COP 3.5) | 350% | 24.67p electricity | 7.05p |
| Oil boiler (new, 90%) | 90% | ~6.1p/kWh oil | 6.78p |
| Oil boiler (old, 70%) | 70% | ~6.1p/kWh oil | 8.71p |
| LPG boiler (new, 90%) | 90% | ~9.8p LPG | 10.89p |
For a typical 12,000 kWh annual heat demand: a heat pump costs approximately £846/year vs £825/year for oil at moderate prices — essentially comparable. But with a smart overnight tariff like Octopus Cosy at 7p/kWh, heat pump running costs drop to approximately £240/year — a saving of over £500/year versus oil.
Add solar panels and the savings compound further: solar-generated electricity can power the heat pump for free during daylight hours.
The Oil Price Problem
Heating oil prices are highly volatile. April 2026 prices are around 132p/litre — significantly elevated due to geopolitical factors, up from moderate levels of ~50–55p/litre. At 132p/litre, an annual heating bill can reach £1,980/year for a typical 3-bed home. At 55p/litre, it would be ~£825/year.
Heat pump running costs do not swing with oil market volatility. Electricity prices move quarterly with the Ofgem price cap, but the swings are far less extreme. For Cornwall households who have watched oil prices double in two years, energy cost certainty is a significant benefit of switching.
There are also the practical issues: oil delivery access on narrow Cornish lanes, large tank footprint in the garden, and the requirement for annual tank maintenance and fuel management.
What the Installation Involves
A typical oil-to-heat-pump conversion takes 2–4 days on site and involves:
- Free home survey — Room-by-room heat loss calculation (BS EN 12831), heat pump sizing, and full design
- Radiator assessment — Heat pumps work best at 35–45°C flow temperature. Typically 3–8 radiators need upsizing to K2 double-panel versions
- Hot water cylinder — A heat pump-compatible cylinder (minimum 200L with oversized coil) replaces your existing tank
- Heat pump installation — External unit on a wall bracket or ground pad, typically in the garden or at the rear of the property
- Oil system decommissioning — Old boiler removed, oil tank decommissioned and removed or left in place
- Controls and commissioning — Weather compensation controller, app setup, MCS certification
From survey to installation: typically 4–8 weeks (the main variable is the BUS voucher approval from Ofgem). See our heat pump installation page for full details.
Cornwall's Ideal Conditions for Heat Pumps
Cornwall's mild Atlantic climate gives it some of the best conditions for heat pump performance in the UK:
- Mild winters — Cornwall rarely experiences prolonged freezing temperatures. Heat pumps perform at their best in mild conditions (outdoor temp 5–12°C), which describes most of Cornwall's winter.
- High COP year-round — Cornwall's mild climate means a well-designed system achieves COP 3.5+ consistently, keeping running costs low.
- Off-grid ready — 47% of Cornwall homes are not on mains gas. The whole infrastructure for off-grid energy solutions (oil delivery, LPG, renewable alternatives) is well established here.
- Solar synergy — Cornwall's 1,298 kWh/m² solar irradiance (19% above UK average) means solar panels + heat pump is the ultimate off-grid solution, with solar powering the heat pump during the day.
Next Steps
If you are heating with oil in Cornwall, the combination of the £9,000 BUS grant for oil homes with no gas main (until March 2027) and Cornwall's ideal heat pump conditions makes this the best time to switch. We serve Cornwall including St Austell, Bodmin, Truro, Lostwithiel, Fowey, Wadebridge, and the entire mid-Cornwall service area.
Book a free home survey — we carry out the heat loss calculation, design the system, handle the BUS application, and provide a fixed-price quote with the grant already deducted.
Need personalised advice?
Our MCS certified engineers can answer your questions and provide a free, no-obligation assessment for your property.