Mains gas
Cheapest fuel per kWh, no on-site storage, most efficient modern combis. Only works if the gas main reaches your street.
Oil (kerosene)
The default for off-grid Somerset homes. Higher per-kWh cost, needs a bunded tank, but reliable and well-supported locally.
Running cost comparison (2026)
| Fuel | Typical cost / kWh | Annual cost, 3-bed home (~12,000 kWh) |
|---|---|---|
| Mains gas | ~6.5 p | ~£780 |
| Heating oil (kerosene) | ~7.5 p | ~£900 |
| LPG | ~10 p | ~£1,200 |
| Air-source heat pump (COP 3) | ~9 p effective | ~£1,080 |
Prices vary with market conditions; oil in particular fluctuates seasonally. Buying oil in summer typically saves 8–15%.
When oil is the right choice
- • Your street has no mains gas and the nearest connection would cost more than £3–5k to run in.
- • You have — or can install — an OFTEC-compliant bunded tank at least 1.8m from the property, 760mm from a boundary.
- • Your home is well insulated (heat pumps struggle in solid-wall stone cottages without upgrades).
- • You want a single fuel source that heats water on demand as well as central heating.
When to consider switching
- • Oil → mains gas: only worth it if gas is within ~30m of the meter position. Ask the DNO for a connection quote first.
- • Oil → LPG: rarely a good move on cost alone — usually chosen for aesthetics (no tank) or a gas hob.
- • Oil → heat pump: best paired with insulation upgrades and larger radiators. BUS grant of £7,500 makes this viable for many rural homes.
Oil tank rules you should know
- • Bunded (double-skinned) tanks are mandatory for domestic installs since 2001.
- • Position: 1.8m from any building opening (window/door), 760mm from a boundary, 600mm from non-fire-rated eaves.
- • Base: 100mm concrete or paving slabs, extending 300mm beyond the tank on all sides.
- • Fire valve required at the appliance end of the fuel line.
- • Installations must be certified by an OFTEC engineer (like us) to satisfy Building Regs.
Local reality check
Across BA3 (Radstock), BS39 (Paulton) and BS40 (Chew Valley) roughly 30–40% of properties we quote are off mains gas. In most cases a modern condensing oil boiler (Worcester Greenstar Heatslave or Grant Vortex Blue) is still the most cost-effective replacement — often £3,400–£4,600 supplied and fitted vs £8k+ for a heat pump before grants.
Related reading
Not sure which is best for your home?
Free site survey — we'll check gas availability, tank placement and give you a like-for-like comparison in writing.