Frequently Asked Questions
The most common questions we get about boiler replacement in the UK, answered in plain English.
How much does it cost to replace a boiler in 2026?
The average cost of a new boiler installation in the UK in 2026 is £2,000-£4,500 including fitting. A straightforward combi-to-combi swap typically costs £1,800-£3,000, while changing boiler type or location adds £500-£2,000 extra for additional pipework.
How long does a boiler installation take?
A like-for-like boiler replacement typically takes 1 day (4-8 hours). If you're changing boiler type (e.g., regular to combi), moving the boiler location, or upgrading the heating system, it can take 2-3 days.
Is it worth replacing a 15-year-old boiler?
Usually yes. A 15-year-old boiler likely runs at 70-80% efficiency. Replacing it with a modern A-rated condensing boiler (90%+ efficient) could save £200-£580 per year on gas bills. Over 10 years, that's £2,000-£5,800 in savings against an average installation cost of £2,500-£3,500.
Do I need to replace my radiators when I get a new boiler?
Not always. If your existing radiators are in good condition and adequately sized, they'll work fine with a new boiler. However, if they're old, corroded, or undersized for your rooms, upgrading them will improve efficiency. A powerflush is recommended to clean the system before connecting a new boiler.
What is the best type of boiler for a 3-bedroom house?
For a typical 3-bedroom house with one bathroom, a combi boiler (28-32 kW) is usually the best choice. It's compact, efficient, and provides instant hot water. If you have two or more bathrooms, consider a system boiler with a hot water cylinder for better flow to multiple outlets.
Can I get a grant for a new boiler?
Yes, several schemes can help. The Boiler Upgrade Scheme offers up to £7,500 towards heat pumps. The ECO4 scheme can fund boiler replacements for low-income households on qualifying benefits. Your local council may also offer grants. Check your eligibility on the GOV.UK website.
What is a Gas Safe registered engineer?
Gas Safe Register is the official registration body for gas engineers in the UK. It replaced CORGI in 2009. By law, anyone working on gas appliances (including boilers) must be on the Gas Safe Register. You can verify an engineer's registration at GasSafeRegister.co.uk or by calling 0800 408 5500.
How long do boilers last?
A well-maintained boiler typically lasts 12-15 years. Some last 20+ years with regular servicing, but efficiency declines significantly after 10-15 years. Annual servicing by a Gas Safe engineer is the single best way to extend your boiler's lifespan.
Should I get a fixed price or a quote for boiler installation?
Always get at least 3 written quotes from Gas Safe registered installers. A fixed-price quote means the price won't change regardless of complications. Be wary of very low quotes — they may not include necessary extras like a magnetic filter, powerflush, or system upgrades.
What warranty should I expect on a new boiler?
Most reputable brands offer 5-12 year warranties on new boilers. Worcester Bosch and Ideal offer up to 12 years. Longer warranties typically require installation by an accredited installer and annual servicing. Always register your warranty within the required timeframe.
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Our detailed cost guide covers everything from pricing to installation, with data verified as of April 2026.
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