Gas Safe registered engineers onlyCompare A-rated boilers.
Warranty and typical fitted price, side by side. No manufacturer pays to appear here and none of these links earn us anything.
| Brand | Typical fitted price | Max warranty | Best suited to |
|---|---|---|---|
| Worcester BoschGreenstar 4000, Greenstar 2000, Greenstar 8000 | £2,300 to £3,200 | Up to 12 years | The safe default. Most engineers fit these weekly, so parts and know-how are everywhere. |
| ViessmannVitodens 100-W, Vitodens 050-W | £2,400 to £3,300 | Up to 12 years | Stainless steel heat exchanger, built to last. The one to ask about if you plan to stay put. |
| VaillantecoTEC plus, ecoTEC exclusive | £2,400 to £3,300 | Up to 10 years | Quiet running. Worth the premium if the boiler sits near a bedroom. |
| IntergasXclusive, Xtreme | £2,300 to £3,100 | Up to 10 years | Very few moving parts, so less to go wrong. Fewer engineers fit them. |
| Baxi800 Combi, 600 Combi, 400 Combi | £2,100 to £2,900 | Up to 10 years | Strong value with a built-in system filter, which most engineers would add anyway. |
| IdealLogic Max, Vogue Max, Logic Combi | £2,000 to £2,800 | Up to 12 years | The most commonly installed boiler in the UK. Simple, and parts are everywhere. |
| Glow-wormEnergy, Betacom, Ultimate | £1,900 to £2,600 | Up to 10 years | Vaillant's budget brand, so it shares a lot of the engineering at a lower price. |
| PottertonAssure, Promax | £1,900 to £2,600 | Up to 7 years | Baxi's budget brand. Sound boiler, shorter warranty than the others here. |
| AlphaE-Tec, E-Tec Plus | £1,900 to £2,600 | Up to 10 years | The cheapest of the recognised names, with a stainless steel heat exchanger. |
How to read these prices
- These are fitted prices, not the price of the box. Supply, installation, flue, standard controls and VAT, for a like-for-like combi swap in an average home. It is what actually leaves your account.
- Manufacturer list prices you see quoted elsewhere are usually the appliance alone, at trade. No homeowner pays those, and treating them as the cost of a new boiler is how people end up shocked by their first quote.
- Moving the boiler, losing a cylinder or a system flush all sit on top. See the full cost breakdown.
Ranges are a guide for a straightforward replacement in an average UK property, including VAT. Warranty lengths are the maximum available and almost always require installation by an accredited engineer plus an annual service. Only an engineer who has seen your property can give you a real price.
Ask three engineers what they would fit.
- Three quotes from Gas Safe engineers in your postcode
- Compare prices and opinions before you commit
- A maximum of three, then it closes
- Free to you, and no obligation
The brand matters less than you think.
Three things beat brand choice, and two of them are about the engineer.
Who fits it
A mid-range boiler fitted properly outlasts a premium one fitted badly, every time. Most early failures are installation, not manufacturing.
Whether it is sized right
An oversized boiler cycles on and off and wears out faster. An undersized one cannot keep up. This is the engineer's job to get right.
Whether you service it
Nearly every long warranty requires an annual service by a registered engineer. Miss one year and the twelve-year cover can be gone.
Questions people ask.
Which boiler brand is most reliable?
Worcester Bosch, Vaillant and Viessmann consistently sit at the top of independent reliability surveys, and all three back it with long warranties. But an engineer who fits one brand every week will get a better result from it than from a brand they rarely touch, so ask what they fit most.
Is a more expensive boiler worth it?
Sometimes. What you are usually buying is a longer warranty, quieter running and a better heat exchanger. Not efficiency: every new gas boiler fitted in England since April 2018 has had to be at least 92% efficient under Boiler Plus, so all of these clear the same bar and the difference between them is about a percentage point.
Can I buy the boiler myself?
You can, but most manufacturer warranties are registered by the installing engineer and many will not fit an appliance they did not supply. The saving is usually smaller than it looks and the warranty risk is real.
Ask three engineers instead.
They will tell you what they would fit in your house, and what it costs. Free, thirty seconds.