Boiler Replacement Cost in London (2026)

A new boiler is one of the bigger bills a home owner or landlord faces, and quotes for what sounds like the same job can be hundreds of pounds apart. The price depends far more on what kind of job it is — a straight swap, a new cylinder, a conversion, a move — than on the boiler itself.

💷 New Boiler Prices in London

Our new-boiler prices include the heating controls the rules require and a magnetic filter. A power flush is only needed if your system has sludge — we check first and tell you before any work starts.

Typical prices are from published 2026 UK and London price guides; London usually runs 10–20% above the rest of the country. We give you a free quote on the phone — a few photos of the boiler, the flue and the cylinder (if you have one) help — then a fixed price before any work starts.

✅ What a Proper Boiler Replacement Involves

When you compare quotes, check each one covers the same work. A correctly installed replacement in England includes:

• Removing the old boiler and fitting the new one, with a new flue that meets the clearance rules for windows, doors and boundaries
• A high-efficiency condensing boiler — under the “Boiler Plus” rules, a new gas boiler in an existing home must be at least 92% efficient
• Heating controls — a timer and a room thermostat are required on every installation. A new combi must also have one energy-saving extra: weather compensation, load compensation, flue gas heat recovery, or a smart thermostat with automation and optimisation
• Protecting the new boiler — boiler makers expect the heating water to be clean and treated with inhibitor for the warranty. A magnetic filter catches dirt before it reaches the boiler (included in our prices). If your system has sludge, it needs a clean or power flush first; we check this and quote it separately
• A proper condensate pipe — ideally inside; outside runs need to be larger and insulated so they don’t freeze
• Commissioning and paperwork — the Benchmark checklist filled in, and the boiler registered for its warranty
• Building regulations notification — a new boiler is notifiable work. The Gas Safe engineer notifies it within 30 days, and Gas Safe Register sends you a Building Regulations Compliance Certificate. Keep it — you’ll need it when you sell

A very cheap quote often leaves out the controls or the notification. Ask what’s included before you compare prices. Our written quote lists everything in the fixed price.

🔍 What Pushes the Price Up

• Changing the type of boiler — removing loft tanks and a cylinder for a combi is more work than a swap. See combi vs system boiler for which suits your home.
• Moving the boiler — to a loft, a cupboard or another room means new gas, water, condensate and flue runs.
• The gas pipe — a combi needs a good gas supply. An old, narrow pipe from the meter may need upgrading.
• The flue — if the old position no longer meets the rules, the flue may need a new route, an extension or a plume kit.
• A dirty system — sludge in the pipes and radiators may need a power flush before a new boiler goes in. Signs: radiators cold at the bottom, noisy pipes, dark water when you bleed a radiator.
• A bigger home — more radiators and bathrooms need a larger boiler, and sometimes a system boiler and cylinder rather than a combi.
• Access — loft installs, top-floor flats without a lift, and parking in central London all add time.

⏱️ How Long It Takes

A like-for-like combi swap is usually done in one day. A system boiler with a new cylinder, a conversion to a combi, or moving the boiler usually takes two to three days. You’ll be without heating and hot water for part of that time, so we agree the dates with you first.

🤔 Do You Actually Need a New Boiler?

Not always. A boiler that keeps breaking down, is over 12–15 years old, or needs a repair costing more than a few hundred pounds is often worth replacing. A younger boiler with one fault is usually worth fixing. Our guide should I repair or replace my boiler? walks through the numbers. If your boiler has stopped, see boiler not working first.

🏠 Landlords and Letting Agents

• A new boiler doesn’t replace the annual gas safety certificate — the yearly check covers every gas appliance and the pipework, and it’s still due on its usual date.
• Keep the Building Regulations Compliance Certificate and the Benchmark checklist with your property records.
• Book an annual boiler service — most manufacturer warranties depend on it. A boiler service and gas safety certificate together is from £120.
• Give tenants notice and agree a date — they’ll be without heating and hot water for part of the installation.

All your certificates for each property are kept in your free client portal, with reminders before they’re due.

🏆 New Boilers from FE Maintenance

• Gas Safe registered, fully insured — every engineer works directly for FE Maintenance, no subcontractors
• Combi swap from £1,900, system boiler with cylinder from £2,500, conversions from £3,500
• Up to 10-year warranty on new boilers
• Heating controls and magnetic filter included; a power flush, if needed, is from £350
• Free quote on the phone, then a fixed price before we start; prices are the total, no VAT added
• Building regulations notification handled for you

We cover North, West and Central London, plus Potters Bar and Hatfield. Call 020 8445 1303, WhatsApp us photos of your boiler and flue, or ask for a quote. See all our gas and boiler services.