New Boiler Installation

A combi boiler heats water on demand with no separate cylinder or tank, which suits smaller households with lower simultaneous hot water demand; a system boiler works with a separate hot water cylinder (good for larger households needing more hot water at once, especially from multiple bathrooms); a regular (conventional) boiler uses both a cylinder and a loft tank, and tends to suit larger or older properties, or a straight replacement where that pipework already exists. The right choice depends on your household size and existing pipework, which is exactly what the survey stage is for rather than defaulting to whichever is currently most popular.

Boiler output needs to match the property's heat demand and hot water usage pattern, not simply be sized up "to be safe" — an oversized boiler actually runs less efficiently because it short-cycles rather than running a longer, steadier cycle. This is calculated from the number of radiators, room sizes, insulation, and (for a combi) the number of bathrooms likely to want hot water at once, which is why a proper survey matters more than picking a size off a shelf.

This depends on whether the space counts as a genuinely new dwelling under current Building Regulations — from 2025, new-build homes are expected to use low-carbon heating (typically a heat pump) rather than a traditional gas boiler as the default, under the Future Homes Standard. An extension to an existing heated home is generally treated differently to a brand new, separate dwelling, so it's worth clarifying which situation applies to your project before assuming either option is automatically available.

Yes — new boilers come with a manufacturer warranty, typically ranging from around 2 years up to 10+ years depending on the model and manufacturer, but nearly all of them require proof of annual servicing by a qualified engineer to remain valid, which is worth factoring into your ongoing costs from the start rather than being caught out later. The installation includes registering the warranty in your name as part of the commissioning process.

This is quoted individually after a survey, based on the boiler type and output your property actually needs — a straightforward like-for-like combi swap costs less than a system change involving new pipework or a cylinder, so a genuine figure only comes after seeing the property.

A like-for-like replacement in a property with existing suitable pipework is often completed in a single day; a change of boiler type, or a flue route that needs altering, extends that. The survey stage gives an honest, property-specific timeline rather than a generic estimate.

As a rough guide, a boiler over 10-15 years old needing repairs more than once a year is usually approaching the point where a new, more efficient boiler makes better long-term financial sense than continued repair bills — see the <a href="/services/boiler-repairs-and-servicing">Boiler Repairs & Servicing page</a> for the repair side of that comparison, and ask for an honest assessment rather than a default recommendation either way.

Finance is available to spread the cost rather than paying the full amount upfront, which is worth asking about at the quote stage if that makes a replacement easier to plan for. On warranty, eligible installations can carry up to a 10-year manufacturer warranty rather than the shorter 2-3 years some installers offer — the exact length depends on the specific boiler and installer accreditation, so ask which warranty length applies to your specific quote rather than assuming the maximum automatically applies.