Gas boiler cost FAQ. Plain answers to UK questions.

A new gas boiler costs £1,800 to £4,500 fully installed. Combi: £1,800 to £3,500. System: £2,000 to £4,500. Conventional: £1,700 to £4,000. Roughly half of the bill is the boiler itself, the other half is labour and parts. Full breakdown on the homepage.

£80 to £120 for a one-off annual service. Local Gas Safe engineers run from £60. National providers like British Gas charge around £99. Boiler cover plans bundle servicing into a £10 to £25 a month subscription. Servicing page.

£300 to £500 for a typical 3-bed home. Costs more if your system has 12+ radiators, more if access is poor. Always optional unless your warranty mandates it. A magnetic system filter (£100 to £150) can be a cheaper preventive alternative for borderline cases.

An Alpha or Ideal Logic combi at the budget end, like-for-like swap, in a low-cost region (North East, Wales, NI), with no extras. Total: £1,800 to £2,300 installed. The same job in London with a premium Worcester would run £3,500 to £4,200.

In London and the South East, yes, by 5 to 15% on average. In low-cost regions, often no, because local Gas Safe engineers can beat the national fixed price. Heatable, BOXT and Boiler Plan all publish national prices that suit metropolitan areas best. Always compare against two local quotes.

1 to 3-bed home with one bathroom and decent mains pressure: combi. 3 to 5-bed with two or more bathrooms: system. Older home with low mains pressure or existing tanks: conventional. Full decision tree on the boiler types page.

A combi heats water on demand and stores nothing. A system heats water and stores it in a hot water cylinder for use across the home. The system handles multiple bathrooms running together; the combi cannot. The combi saves space; the system needs cylinder space.

Yes. Regular-to-combi conversion typically costs £2,500 to £4,000 and takes 2 to 3 days. Tank and cylinder come out, all hot-water pipework reroutes through the new combi. Confirm your mains has at least 1.5 bar pressure and 12 lpm flow before committing.

Combi: 10 to 15 years. System: 12 to 15. Conventional: 15 to 20. Annual servicing by a Gas Safe engineer is the largest single factor in reaching the higher end of each range.

At the Q2 2026 Ofgem cap (5.74p/kWh plus 29.09p/day standing charge), a 3-bed semi using 12,000 kWh costs about £790 a year for heat and hot water. A 1-bed flat: £480 to £540. A 4-bed detached: £1,000 to £1,150. Full table on the running costs page.

Gas: 5.74p/kWh. Electricity: 24.5p/kWh. Per useful kWh of heat, gas is roughly 4 times cheaper than direct electric heating. A heat pump narrows the gap because each kWh of electricity produces 3 to 4 kWh of heat. Full comparison.

Heating flow temperature 60°C on a combi for best condensing efficiency. Hot water 60 to 65°C to stay above the legionella threshold. Room thermostat 20°C in living areas, 18°C in bedrooms. Dropping flow temperature is the single highest-ROI change most homes never make.

Most likely cause: insulation. A poorly insulated 3-bed semi uses 17,000 to 19,000 kWh; a well-insulated one 10,000 to 12,000. Other drivers: thermostat above 21°C, hot water above 65°C, very high shower flow, old boiler at 80% efficiency or worse. Run through the save money page.

Only in new-build homes from 2035. Existing homes are unaffected. The Future Homes Standard regulates new construction, not retrofitting. Full policy explainer.

Yes. The 2035 measure stops new gas boilers in new-build homes. Existing homeowners can buy, fit, replace and service gas boilers indefinitely. Government policy continues to support gas heating in existing stock through normal regulatory frameworks.

A boiler that runs on natural gas today and can be converted to 100% hydrogen by a Gas Safe engineer in a single visit, if the gas grid is converted. Most major UK brands now sell hydrogen-ready models at no price premium. Worth choosing as a low-risk future option.

The Future Homes Standard sets emissions requirements for newly built homes in England. New builds from 2025 must produce 75 to 80% fewer emissions than under the 2013 regs. From 2035, new gas boilers cannot be fitted in new builds. Existing homes are out of scope.

Possibly through ECO4 if you receive Universal Credit, Pension Credit or qualify under LA Flex (low income plus EPC D-G plus a vulnerability). The scheme replaces inefficient 8+ year boilers at no cost. 2026 outlook: limited funding remaining. Apply if you qualify, plan for paid replacement. Grants page.

The fourth phase of the Energy Company Obligation, running to December 2026. Major UK energy suppliers fund energy-efficiency upgrades for low-income and vulnerable households. Includes free A-rated boiler replacements where the existing boiler is inefficient and 8+ years old.

Direct ECO4 route: you must receive Universal Credit, Pension Credit, Income Support, ESA, JSA or Child Tax Credit. LA Flex route: low income (under £31,000 typically), EPC D-G, plus a vulnerability factor (children under 5, residents over 65, respiratory or cardiovascular condition). Final eligibility is decided by the installer and your local council.

Like-for-like combi swap: 1 day. Combi relocation: 1.5 to 2 days. Regular-to-combi conversion: 2 to 3 days. Full system change: 2 to 3 days. Detail on the installation page.

Yes for the start (engineer access), the gas-on safety walk-through (mid-morning of day 1), and the final commissioning and hand-over. Most engineers prefer the homeowner present throughout in case access decisions need approval. You do not need to take the entire period off work, but expect to be home for at least 4 to 6 hours.

The Gas Safe Register is the UK's official list of engineers qualified to work on gas appliances. Replaced CORGI in 2009. Every gas installation in the UK must be done by a Gas Safe registered engineer or company. Verify at gassaferegister.co.uk and check the engineer's ID card on arrival.

Annually. Best timing: late summer or early autumn before the heating season. Landlords are legally required to obtain a CP12 gas safety certificate annually. Owner-occupiers face no legal obligation but every major UK manufacturer requires annual servicing to keep the warranty valid.