The short answer: a new boiler in Sussex typically costs between £1,700 and £4,500 +VAT fitted, depending on the type of boiler, its output, the brand, and how complex the installation is. A straightforward like-for-like combi swap sits at the lower end, while a premium boiler with extras such as a powerflush, smart controls, or a change of boiler type pushes towards the upper end.
Boiler pricing is one of the most common questions we get from homeowners across Sussex, and there is a lot of confusing and contradictory information online. This guide breaks down the real costs in 2026 — by boiler type, by what actually drives the price, and what you get for your money — so you can budget with confidence.
How much does a new boiler cost in 2026?
For most homes, a new gas boiler supplied and installed costs somewhere between £1,800 and £4,500. Independent figures back this up. The Energy Saving Trust puts the cost of replacing an old G-rated boiler with a new A-rated model at around £2,500 to £4,000, and Checkatrade's 2026 cost guide reports a similar national spread depending on boiler type and brand.
Sussex and the wider South East tend to sit at the higher end of national averages because labour rates here are slightly above the UK norm. The good news is that the boiler itself — the single biggest part of the cost — is priced the same wherever you are.
Boiler prices by type
Combi boiler: £1,800–£3,500
A combi (combination) boiler heats your water on demand and is the most popular choice in UK homes, especially flats and smaller properties. Because there is no separate hot water cylinder or tank, a like-for-like combi swap is usually the most affordable installation. Most combi replacements in Sussex fall between £1,800 and £3,500 fitted, depending on the brand and output.
System boiler: £2,000–£4,500
A system boiler works with a hot water cylinder and suits larger homes with more than one bathroom, where several taps may be running at once. The boiler itself is similar in price to a combi, but the wider system means installation can cost a little more. If you are weighing up your options, our guide on combi vs system boilers explains which suits which home.
Conventional (heat-only) boiler: £2,000–£4,500
Conventional or "heat-only" boilers use both a hot water cylinder and a cold water tank in the loft. They are most common in older Sussex properties. Replacing like-for-like is straightforward, but converting to a combi adds cost (more on that below).
What affects the cost of a new boiler?
- Boiler type and output (kW): A boiler must be correctly sized to your home. Too small and it will struggle; too large and you waste money on the unit and running costs. Our boiler sizing guide explains how this is worked out.
- Brand: Premium brands such as Worcester Bosch and Vaillant cost more than budget alternatives but typically come with longer warranties and better reliability. See our honest review of the best boiler brands.
- Like-for-like vs a change of type or location: Swapping the same type of boiler in the same spot is the cheapest job. Moving the boiler to a new location, or converting from a conventional system to a combi, means new pipework and flue runs and adds significantly to the cost.
- System extras: A power flush, new radiators, a magnetic filter, a smart thermostat, or upgraded condensate pipework all add to the total — but often pay for themselves in efficiency and reliability.
- Complexity: Awkward access, gas pipe upgrades, or older systems that need extra work will affect the final price.
What does a new boiler cost with Platinum Boilers?
We keep our pricing simple and transparent with three fixed-price packages. Every quote is a Guaranteed Fixed Price — the price we quote after a free survey is the exact price you pay, with no hidden extras or call-out charges.
- Silver — from £1,700 +VAT: A new A-rated boiler supplied and fitted, standard flue, magnetic filter, removal of your old boiler, full commissioning, and Building Regs notification. Ideal for a straightforward like-for-like swap.
- Gold — from £2,150 +VAT: Everything in Silver, plus a full system cleanse, premium filter upgrade, a smart thermostat, and thermostatic radiator valves. Our most popular package.
- Platinum — from £3,800 +VAT: A premium A-rated boiler, full powerflush where required, radiator balancing, smart room-by-room controls, and the highest warranty options (up to 10–12 years).
Common add-ons are priced clearly too — for example, boiler relocation from £450, a gas pipe upgrade from £250, or a heat-only to combi system conversion from £1,200. You can see the full breakdown on our pricing page.
Will a new boiler save me money?
Yes, usually. Every new gas boiler sold in the UK is A-rated, meaning over 90% efficient, compared with around 70% or less for an old G-rated unit. The Energy Saving Trust estimates that replacing an old, inefficient boiler with a new A-rated model can save a typical household up to around £300 a year on energy bills.
To be straight with you: real-world efficiency is often a little below the lab rating, so treat headline savings as a best case. But a modern, correctly-sized and well-installed boiler will still be noticeably cheaper to run — and far more reliable — than an ageing one.
How to keep the cost down
- Always get a fixed price after a proper survey, not a vague figure over the phone. It protects you from surprise charges.
- Stick to like-for-like where it makes sense — keeping the same boiler type and location avoids the biggest extra costs.
- Don't over-size the boiler. Bigger is not better; the right output for your home is what matters.
- Check whether you qualify for a grant. Some households can get help towards a new boiler — see our guide to boiler grants and the ECO4 scheme in Sussex.
- Service it annually to protect both efficiency and your warranty.
FAQ
How much is a new combi boiler in Sussex?
A new combi boiler in Sussex typically costs between £1,800 and £3,500 fitted for a like-for-like swap, depending on the brand and output. Our Silver package starts from £1,700 +VAT, including supply, installation, removal of the old boiler, and full commissioning.
Does the price include removing my old boiler?
With Platinum Boilers, yes. Every package includes removal and disposal of your old boiler, a magnetic filter, full commissioning and safety checks, and Building Regulations notification. There are no separate call-out or disposal charges.
Is it cheaper to repair or replace my boiler?
If your boiler is over 10 years old and a repair would cost more than around half the price of a new unit, replacement is usually the better long-term decision. A new A-rated boiler is more efficient, more reliable, and comes with a manufacturer warranty. Read our guide on the signs it's time to replace your boiler.
Are there any grants to help with the cost?
Possibly. The ECO4 scheme can help qualifying households towards a new boiler, and the Boiler Upgrade Scheme offers grants for heat pumps. Our boiler grants guide explains who is eligible and how to apply.
How long does a new boiler installation take?
A standard like-for-like swap is usually a one-day job. More complex installations, such as a system conversion or relocation, can take one to two days. See our guide on how long a boiler installation takes.
Want an exact figure for your home rather than a range? Platinum Boilers provides free surveys and Guaranteed Fixed-Price quotes on new boilers across the whole of Sussex, from Brighton and Worthing to Lewes and Eastbourne. Get your free quote in under two minutes and we'll do the rest.
