The Fentons live in a Grade II-listed stone farmhouse in a hamlet just outside Clitheroe (BB7). Their heating had been on a 22-year-old oil-fired boiler paired with an original 1980s Aga range in the kitchen. The oil tank finally sprang a leak in March 2026, and rather than swap oil-for-oil, they wanted mains gas — which had reached the village three years earlier. This was our biggest fuel-switch job of the spring.
The property
4-bed stone farmhouse in the Ribble Valley (BB7). Thick stone walls, original beams, minimal insulation, ten radiators (some cast-iron column, some panel), one family bathroom + en-suite off master, downstairs cloakroom. Cold-water mains at a healthy 3.1 bar once the new gas supply arrived. Water hardness in BB7 sits at around 195 ppm — moderate.
Why we chose a system boiler, not a combi
Two bathrooms, 10 radiators, thick stone walls (huge heat-loss factor) and a family that likes long baths — a combi was going to be undersized. Plus the Fentons wanted to keep their existing 220L unvented cylinder in the utility (fitted in 2015, still perfect), so a system boiler feeding into it was the correct spec.
The fixed-price quote
We specified a Worcester Bosch Greenstar 4000 30 kW system boiler, retained the existing 220L Range Tribune HE cylinder (with a compliance re-check on the G3 kit), and added a Nest Learning Thermostat wired to two zones. Total fixed price: £3,850 — including the boiler, a new external gas meter run (10 m of MDPE from the boundary), commissioning of the existing cylinder, chemical flush of all 10 radiators, MagnaClean, F1 inhibitor, disposal of the old oil boiler and tank, and full Building Control notification. 10-year Worcester warranty.
The install (4 days)
- Day 1: Isolated the oil boiler. Cut in the new gas supply from the meter (arranged the meter install with Cadent the previous week). Ran 22 mm gas from the meter to the boiler location in the utility.
- Day 2: Removed the 22-year-old oil boiler, flue and controls. Fitted the Worcester Greenstar 4000 System. Re-commissioned the existing 220L unvented cylinder with a fresh G3 compliance check (expansion vessel pre-charge, T&P valve test, D2 discharge integrity).
- Day 3: Wired the two-zone motorised valves. Fitted the Nest Learning Thermostat and two zone stats. Chemical hot flush of all 10 radiators (drained overnight to loosen sludge in the cast-iron columns).
- Day 4: F1 inhibitor dose. Full commissioning of the new boiler. Removed the empty oil tank and the sludge-cleared trays it stood on. Building Control notified via Gas Safe. 10-year Worcester warranty registered.
The savings
Oil at 78 p/L (Feb 2026 average) vs mains gas at 6 p/kWh — the Fentons' heating bill dropped from £2,900/yr (oil + servicing) to a projected £1,700/yr (gas + servicing). That's a £1,200/year saving — the fuel-switch investment pays back inside 3 years.
Why the Ribble Valley suits system boiler upgrades
BB7 has a lot of larger, older stone properties (Whalley, Waddington, Chatburn, Slaidburn) where oil is common and gas is now arriving. Once mains gas is available, a proper system boiler + unvented cylinder is the right answer for houses too big for a combi. If you're considering an oil-to-gas switch, we do the whole job start to finish — including the Cadent liaison — for a single fixed price.
Clitheroe / Whalley / Ribble Valley boiler upgrade? Start the instant boiler quote or see our Clitheroe boiler installer page.
