Gas Boiler Cost FAQ
Your Questions Answered
Everything you need to know about gas boiler costs in the UK, answered plainly with specific 2026 data.
Updated April 2026
Costs
How much does a gas boiler cost?
A new gas boiler costs £1,800 to £4,500 supplied and fitted in the UK in 2026. The price depends on boiler type (combi, system, or conventional), brand tier (budget, mid-range, or premium), property size, installation complexity, and region. London costs 25-35% more than the North East.
Read the full guideHow much is a boiler service?
A one-off boiler service costs £80 to £120 nationally. A local Gas Safe engineer charges £60 to £90, while British Gas charges £99. Annual servicing is essential to maintain warranty and efficiency. Late summer is the best time to book.
Read the full guideHow much does a powerflush cost?
A powerflush costs £300 to £500 for a typical 3-bed home with 8-10 radiators. It is recommended when installing a new boiler in a system over 10 years old. A chemical system cleaner is a cheaper alternative at £100 to £200 but less effective.
Read the full guideWhat is the cheapest boiler to install?
A budget combi boiler from Ideal or Alpha costs £1,800 to £2,200 installed for a like-for-like swap. The cheapest possible installation is a same-position combi swap with a budget brand in the North East: roughly £1,700 to £2,000.
Read the full guideAre online boiler companies cheaper?
Often yes, by 10-15%. Companies like Heatable and BOXT offer fixed national pricing with manufacturer-accredited installers. This is particularly good value in London and the South East where local quotes are highest.
Read the full guideTypes
What type of boiler do I need?
Combi boilers suit 1-3 bed homes with one bathroom. System boilers suit 3-5 bed homes with two or more bathrooms. Conventional boilers suit older properties with existing tank and cylinder setups. If you have two or more bathrooms, a combi will struggle to supply hot water to multiple taps at once.
Read the full guideWhat is the difference between combi and system?
A combi heats water on demand with no storage. A system boiler stores hot water in a cylinder. Combi is cheaper to install and needs less space. System handles multiple bathrooms better and is compatible with solar thermal.
Read the full guideCan I convert from regular to combi?
Yes, but it costs more than a like-for-like replacement. A conventional-to-combi conversion costs £2,500 to £4,000 because the cylinder and loft tank must be removed and pipework rerouted. It frees up space but only makes sense for smaller homes.
Read the full guideHow long do boilers last?
Combi boilers last 10 to 15 years. System boilers last 12 to 15 years. Conventional boilers can last 15 to 20 years. Annual servicing is the single biggest factor in boiler longevity. Without servicing, lifespan drops significantly.
Read the full guideRunning Costs
How much does it cost to run a gas boiler per year?
At the Q2 2026 Ofgem cap rate of 5.74p/kWh, a 1-bed flat pays roughly £500 to £620 per year. A 3-bed semi pays £780 to £950. A 5-bed detached pays £1,300 to £1,500. These figures include heating and hot water but not the gas standing charge (£106/year).
Read the full guideIs gas or electric cheaper?
Gas costs 5.74p/kWh versus 24.5p/kWh for electricity at Q2 2026 cap rates. Gas is roughly 4.3 times cheaper per unit. Heat pumps narrow the gap because they generate 2.5 to 4.5 kWh of heat per 1 kWh of electricity, but for direct heating, gas wins comprehensively.
Read the full guideWhat temperature should my boiler be set to?
For a combi boiler, set the flow temperature to 60C for best efficiency. The room thermostat should be at 19 to 21C. For system and conventional boilers, the cylinder thermostat should be 60C. Never go below 55C for the cylinder to prevent legionella.
Read the full guideWhy is my gas bill so high?
Common causes: poor insulation, an old inefficient boiler (under 80% efficiency), high thermostat settings (above 21C), heating on all day instead of timed periods, draughty windows and doors, or an undersized boiler working harder than necessary.
Read the full guidePolicy
Are gas boilers being banned?
From 2035, new-build homes in England cannot have gas boilers as the primary heating system. Existing homes are not affected. You can still buy, install, and replace a gas boiler in your current home after 2035. There is no forced switchover for existing properties.
Read the full guideCan I still get a gas boiler after 2035?
Yes, in an existing home. The 2035 ban applies only to new-build homes. Gas boilers will continue to be manufactured, sold, installed, and serviced in existing properties for decades to come.
Read the full guideWhat is a hydrogen-ready boiler?
A hydrogen-ready boiler runs on natural gas today but can be converted to hydrogen if the gas network switches. Most major brands offer hydrogen-ready models at no or minimal extra cost (£0-200). There is no downside to buying one, but do not expect hydrogen for home heating anytime soon.
Read the full guideWhat is the Future Homes Standard?
The Future Homes Standard requires new-build homes from 2025 to produce 75-80% fewer carbon emissions than current Building Regulations. From 2035, new builds cannot have gas boilers. Existing homes are exempt from all of these requirements.
Read the full guideGrants
Can I get a free boiler?
Potentially, through the ECO4 scheme if you receive qualifying benefits and have an old, inefficient boiler in a home rated EPC D or below. However, ECO4 funding is nearly exhausted in 2026 and new applications are increasingly difficult. Apply through your energy supplier.
Read the full guideWhat is ECO4?
ECO4 is the Energy Company Obligation scheme that requires large energy suppliers to fund heating and insulation improvements for eligible low-income and vulnerable households. Qualifying benefits include Universal Credit, Pension Credit, and various tax credits.
Read the full guideDo I qualify for a boiler grant?
You may qualify for ECO4 if you receive means-tested benefits and your home has an EPC of D or below. The BUS grant (£7,500) is available to any homeowner but only for heat pumps, not gas boilers. Some local councils offer additional grants through the LA Flex route.
Read the full guidePractical
How long does installation take?
A like-for-like combi swap takes 4 to 6 hours (one day). Relocating the boiler adds half a day. Converting between types (e.g. conventional to combi) takes 2 to 3 days. You will be without heating and hot water for the duration.
Read the full guideDo I need to be home during installation?
Yes. The engineer needs access to the boiler, gas meter, water stopcock, and all radiators. Someone over 18 should be present throughout. The engineer will also need to commission the boiler and walk you through the controls.
Read the full guideWhat is Gas Safe?
Gas Safe Register is the official list of engineers qualified to work on gas appliances in the UK. It is illegal for anyone not on the register to do gas work. Always verify your engineer's Gas Safe ID before allowing them to start work. Check at gasaferegister.co.uk.
Read the full guideHow often should I service my boiler?
Once a year, every year. The best time to book is August or September, before the heating season rush. Annual servicing maintains efficiency, keeps your warranty valid, and checks for carbon monoxide leaks. A service costs £80 to £120 and takes 30 to 45 minutes.
Read the full guide