Boiler Installation London — Gas Safe Registered Engineers

A new combi boiler fully installed — including all pipework modifications, flue, controls and commissioning — typically costs £2,200–£3,500 for a standard back-boiler replacement or like-for-like swap. Converting from a conventional to a combi boiler (removing the hot water cylinder and cold tank) is £2,800–£4,500 depending on the amount of pipework involved. Worcester Bosch and Vaillant are the most reliable long-term choices; both come with 10-year manufacturer warranties when installed by an accredited installer.

A like-for-like combi boiler replacement typically takes 6–8 hours — one working day. A full conversion from conventional to combi (removing a hot water cylinder and cold water tank in the loft) takes 1–2 days depending on the amount of pipework rerouting required. We give you a fixed time estimate when we quote.

Worcester Bosch and Vaillant are the most reliable makes in our experience — both have good parts availability and offer 10-year warranties on their premium ranges when installed by accredited engineers. Ideal is a solid mid-range option. Baxi is also reliable and competitively priced. We'll recommend the most suitable model for your property's hot water demand and heating system — a combi isn't right for every house.

Yes. Old boiler removal and disposal is included in our installation price. We disconnect the old appliance safely, cap off any redundant pipework, and take the unit away. If you're having a hot water cylinder and cold tank removed as part of a combi conversion, that's included too.

We commission and fully test the boiler on installation day and register the manufacturer warranty in your name. We recommend an annual service from year 2 onwards — these are typically £85–£120 and take around 45 minutes. Annual servicing is a condition of most manufacturer warranties.

Most boiler manufacturers require evidence of system cleanliness as a condition of the full warranty. If your system is more than 10 years old or has a history of radiator problems, a power flush before the new boiler is installed is strongly recommended. Installing a new boiler into a sludged system is the most common cause of premature heat exchanger failure — and warranty claims resulting from dirty system water are often rejected. We assess system condition during the site survey and include power flushing in our quote if needed.

Not necessarily — radiator cold spots are usually caused by sludge in the radiators, not boiler failure. A new boiler with a magnetic filter prevents new sludge forming, but existing sludge needs removing via power flush first. If you have cold radiators currently, we include a power flush in the installation package — fitting a new boiler without flushing means the sludge damages the new heat exchanger within 2–3 years.

We disconnect, drain and remove your old boiler as part of the installation price. The old unit is taken away for responsible disposal — old boilers contain materials that require specialist recycling. If you're having a combi conversion (removing a hot water cylinder and cold water tank), we remove and dispose of those too.

Any Gas Safe registered engineer can legally install a boiler. An accredited installer is specifically trained and assessed by the manufacturer — Worcester Bosch's Accredited Installers and Vaillant's Advanced Installers unlock longer warranty terms (typically 10 years vs 5 years for standard installation). We install as accredited installers for the main brands, which maximises your warranty term at no extra cost to you.

Yes. Flat boiler installations have some additional considerations: flue routing must comply with Building Regulations Part J (minimum distances from windows, doors and ventilation openings), shared flue systems in apartment blocks require freeholder/managing agent approval, and some older mansion blocks have shared gas risers with limited pressure capacity. We survey the flat before quoting to identify any constraints.