New Boiler Cost UK: What You'll Actually Pay in 2026

Cost Guide 2026

New Boiler Cost UK

If your boiler's on its way out, the first question is always the same: how much is this actually going to cost? Prices vary depending on the type of boiler, your property, and the complexity of the job — here's a straight breakdown of what homeowners across Dartford, Kent, Essex and the South East are paying in 2026.

Average New Boiler Cost in 2026

Most homeowners pay somewhere between £1,800 and £4,500 for a fully installed new boiler, with a straightforward like-for-like combi swap typically landing around £2,200–£3,000. The exact figure depends on boiler type, brand, property size, and whether it's a simple swap or a more involved job.

Job Type	Typical Cost (Installed)
Like-for-like combi replacement	£1,800 – £3,000
System boiler replacement (with cylinder)	£2,200 – £4,000
Conventional/regular boiler replacement	£1,800 – £3,000
Converting regular boiler to combi	£3,000 – £4,500+
Back boiler to combi conversion	£3,500 – £6,000

What Affects the Price?

1. Boiler Type

Combi boilers are the cheapest and most common option for smaller and medium homes, heating water on demand with no tank required. System boilers use a hot water cylinder and suit larger homes with more than one bathroom. Conventional boilers need both a cylinder and a loft tank, and tend to appear in older properties.

2. Boiler Size (kW Output)

A typical 3-bed semi is usually well served by a 24–30kW combi, while larger homes with multiple bathrooms often need 35kW or more. Our engineers carry out a proper heat loss assessment on every quote so you're not guessing on size.

3. Like-for-Like vs Relocation or Conversion

Swapping an existing combi for a new one in the same spot is always the cheapest option, since the pipework, flue and gas supply are already in place. Moving the boiler, or converting from a regular system to a combi, adds cost for new pipework, cylinder removal and extra labour time.

4. Brand

Premium brands like Worcester Bosch and Vaillant sit at the higher end of the price range, but come with stronger reliability records and longer warranties. Mid-range brands like Baxi and Ideal offer solid performance for a lower upfront cost.

5. Extras Worth Factoring In

• Magnetic filter, protects the new boiler from debris: typically £80–£150 fitted
• Power flush, if your system has sludge or cold spots: typically £300–£500
• Smart thermostat upgrade: varies by model

Worth knowing: most boilers last 10–15 years with regular servicing. If yours is approaching that age and repairs are becoming more frequent, it's often more cost-effective to replace than keep patching it up — our repair or replace guide walks through exactly how to make that call.

Why the Exact Quote Matters More Than a Headline Figure

Every home is different, and a fair quote should reflect that rather than a flat, generic price. When we quote for a new boiler installation, we take the time to assess your existing system, your property's heat loss, and what you actually need, not just what fits a standard package. That's why we always recommend a proper in-person survey rather than relying on an online estimate alone.

Our Gas Safe registered engineers install Worcester Bosch, Vaillant, Baxi and Ideal boilers across Dartford, Kent, Essex, Sussex and London, with clear, itemised quotes and no pressure. Find out more about our boiler installation service.