How Much Does a New Boiler Cost in Kingston? 2026 Price Guide

If you're a homeowner in Kingston upon Thames or the surrounding area thinking about a new boiler this year, you're not alone — older combis fitted in the early-to-mid 2010s are now reaching the end of their efficient life, and the cost of running one through another London winter climbs every year they're kept going.

Nationally, a straightforward like-for-like combi boiler replacement typically runs £2,500–£4,000 supply and fit. Upgrading to a system boiler with a new cylinder is usually around £3,000 upwards, and a conventional (heat-only) boiler replacement sits in a similar range. These are UK-wide averages — the exact figure for your home depends on the boiler size, brand, and how much of the existing pipework and flue route can be reused versus changed.

A simple, like-for-like swap is typically a single day's work — most engineers work to a day rate, and a straightforward installation takes around 4–6 hours of that day. Moving the boiler to a new location, converting from a conventional system to a combi, or fitting a new unvented cylinder usually adds a day or two, because of the extra flue, gas and condensate runs involved.

The most common mistake we see is an oversized boiler. A 35kW combi in a two-bedroom flat will short-cycle, wear out faster, and cost more to run than a properly sized 24–28kW unit. A proper heat-loss survey — checking room sizes, insulation, radiator count and hot water demand — is what actually determines the right size, not a guess based on the number of bedrooms.

If your home has one bathroom and modest hot water demand, a combi usually makes sense — no cold water tank in the loft, no hot water cylinder taking up airing cupboard space. If you've got two or more bathrooms, or showers tend to run at the same time in your household, a system boiler with an unvented cylinder is normally the better fit — a combi will disappoint the moment two people want hot water at once.

Any boiler quote given without someone actually looking at your property is a quote that's likely to change on installation day. We survey first, then give you a fixed written price — the number you're quoted is the number you pay, regardless of what we find once the old boiler's out.