No single brand wins outright — the right boiler pairs the output your radiator count needs with a warranty matched to how long you are staying. Worcester runs from the Greenstar 1000 at £1,999 to the 8000 at £2,899; the Vaillant ecoTEC plus at £2,699 is our pick for larger properties; and the Baxi 600 at £2,199 is the best warranty-per-pound we fit.
Worcester Bosch
The range we fit most, in three tiers. The Greenstar 1000 at £1,999 is the budget entry — a solid choice for a flat or small terrace, 5 year warranty. The Greenstar 4000 (£2,699) and 8000 (£2,899) are the step up: quieter, better hot-water performance, worth it in a family home with a power shower, both on 10 year warranties. Details on our Worcester page.
Vaillant
One model on our list, deliberately: the ecoTEC plus at £2,699 with a 10 year warranty. It is our pick for larger properties and for anyone who wants parts availability for years to come. Our Vaillant page has the rest.
Baxi and Main
Baxi covers both ends. The Baxi/Main Eco Compact at £1,999 shares the budget slot with the Worcester 1000 — Main being Baxi's sister brand. The Baxi 600 at £2,199 is the quiet star of the list: a 7 year warranty at a near-budget price makes it the best warranty-per-pound we fit. See Baxi and Main.
What an engineer weighs that a brochure doesn't
The brochures all say roughly the same thing, so here is what actually differs from where we stand — fitting and working on these boilers rather than reading about them.
Parts availability
When a boiler does eventually need a part, what matters is how fast that part can be in an engineer's hand. Worcester and Vaillant both have extensive parts networks — common components are stocked at local merchants, so a repair rarely waits on a delivery. Baxi parts have a different virtue: they are inexpensive and widely stocked, which keeps repair bills modest across the boiler's life. None of the four leaves you hunting for obscure components, which is part of why our install list is these four and no others.
Service and warranty small print
Every warranty on our list — 5, 7 or 10 years — carries the same two conditions people miss. The boiler must be registered with the manufacturer after install (we do this for you), and it must be serviced every year by a Gas Safe engineer, with the record kept. Miss a service and the manufacturer can refuse a claim. The small print also cares how the boiler was installed: manufacturers expect the system to have been cleansed and, on most long warranties, protected with a magnetic filter. That is not upsell — it is what keeps a 10 year warranty worth the paper. All of it is included in our fitted prices, so the cover stands from day one.
Fitting the cupboard, not just the house
Physical size matters more than people expect. Plenty of Birmingham combis live in kitchen cupboards sized around the old boiler, and the premium ranges are often physically larger — a Greenstar 8000 is a bigger box than a Greenstar 1000, and it does not care how good it is if it will not fit the gap. Flue options differ too: how far a flue can run, what bends are allowed and what plume kits exist varies by range, which occasionally decides the brand for a boiler in an awkward spot. This is exactly the sort of thing the free survey settles — we measure the space and the flue route before the quote names a model.
How to actually choose
Ignore brand loyalty and ask two questions: what output do my radiators need, and how long am I staying? Short stay in a small place — take the budget pair. Staying put — the Baxi 600 or a 10-year Worcester or Vaillant earns its extra cost across the warranty. The three-question finder walks you through it.