Which boiler brand do plumbers recommend?

Worcester Bosch and Vaillant come up most often, mainly because parts are stocked at every plumbers' merchant and the diagnostic tools are standardised. Viessmann is the technical connoisseur's choice but harder to source parts for outside cities. This describes how widely brands are fitted and supported rather than a published survey ranking, and it predicts repair cost in year 8 rather than technical quality.

Is Worcester Bosch worth the extra cost?

The supply premium over Ideal or Baxi is £200 to £400. For that you get a very well supported parts network, a warranty to 12 years on the Greenstar 8000 through a Worcester accredited installer, and familiar diagnostics. Ideal matches 12 years on the Vogue Max, so Worcester is not alone at the top. The premium pays back in lower repair friction rather than warranty length.

Which boiler has the longest warranty?

Twelve years is the ceiling, reached without extra payment only by the Worcester Bosch Greenstar 8000 through a Worcester accredited installer and by the Ideal Vogue Max. It is the Vogue Max, not the cheaper Logic Max, that carries Ideal's 12 years: the Logic Max is 10. Viessmann starts the Vitodens 200-W at 7 years with a chargeable upgrade to 10 or 12. Vaillant tops out at 10 via an Advance installer, Baxi 10 on the Platinum, Alpha 2 to 7. All require registration within 30 days, the specified filter and an annual service.

Are cheap boilers a false economy?

Not necessarily. An Ideal Logic Max combi carries 10 years when registered inside 30 days and serviced annually, and fitted by a competent engineer it will usually see that out. The very budget end (sub-£500) has shorter warranties and parts issues. Mid-range is the value sweet spot.

Brand-by-brand / 8 min read

Brand comparison / Page 06

Best gas boiler brands UK 2026.

Worcester Bosch, Vaillant, Viessmann, Baxi, Ideal or Alpha. Warranty terms with the conditions that actually gate them, ErP efficiency, indicative supply prices and how widely each brand is fitted.

Brand	Supply price	Max warranty	Top efficiency	Installer familiarity
Worcester Bosch	£900 to £1,800	Up to 12 yr (accredited installer)	94%	Very common
Vaillant	£850 to £1,600	Up to 10 yr (Advance installer)	94%	Very common
Viessmann	£800 to £1,500	7 yr, paid upgrade to 10 or 12	Up to 98% (Vitodens 200)	Niche
Baxi	£600 to £1,200	Up to 10 yr (with Adey filter)	92%	Common
Ideal	£500 to £1,000	10 yr Logic Max, 12 yr Vogue Max	92%	Common
Alpha	£400 to £800	2 to 7 yr	92%	Less common

Warranty terms and ErP efficiency figures come from each manufacturer's own warranty and product pages, checked 1 October 2026: Worcester Bosch, Vaillant (Advance Protection Kit), Viessmann, Baxi, Ideal (boiler warranties guide) and Alpha. Maximum lengths all carry conditions, which is why the column names them. Supply prices are indicative ranges for the top combi and system models in each range, gathered from UK merchant listings in April 2026 and not re-checked since, so treat them as a guide to relative positioning rather than a current quote. Installer familiarity is our own description of how widely each brand is fitted and how easily parts are found, not a ranking from a published survey. We do not publish Which? brand scores: they sit behind a Which? membership paywall and we will not reproduce or estimate them. Check them directly at which.co.uk/reviews/boilers.

Worcester Bosch

Greenstar 4000, 8000

Supply: £900 to £1,800
Warranty: Up to 12 yr (accredited installer)
Efficiency: 94%

Strengths

Reliability and parts availability
Engineer familiarity nationwide
Long warranties when fitted by accredited installer

Watch outs

Premium pricing on supply
Some models are noisier than rivals

Vaillant

ecoTEC plus, ecoFIT pure

Supply: £850 to £1,600
Warranty: Up to 10 yr (Advance installer)
Efficiency: 94%

Strengths

Quiet operation, German engineering heritage
Highly efficient at part load
Easy to service for trained engineers

Watch outs

Parts more expensive than Worcester
Slightly smaller installer base outside metros

Viessmann

Vitodens 100-W, 200-W

Supply: £800 to £1,500
Warranty: 7 yr, paid upgrade to 10 or 12
Efficiency: Up to 98% (Vitodens 200)

Strengths

Highest efficiency in market on flagship 200-W
Compact design, premium build quality
Warranty can be extended to 12 years if you pay for it

Watch outs

Smaller UK installer network
Some parts on longer lead times

Baxi

800, Platinum

Supply: £600 to £1,200
Warranty: Up to 10 yr (with Adey filter)
Efficiency: 92%

Strengths

Strong value for money
British heritage brand, established parts supply
Reliable mid-range performance

Watch outs

Less refined finish than Worcester or Viessmann
Shorter warranty on entry models

Ideal

Logic Max, Vogue Max

Supply: £500 to £1,000
Warranty: 10 yr Logic Max, 12 yr Vogue Max
Efficiency: 92%

Strengths

Excellent value at the budget end
Compact, easy install
Ten years on the Logic Max, which is long for the price

Watch outs

Less prestige
Mixed reliability data on older Logic models

Alpha

E-Tec, Evoke

Supply: £400 to £800
Warranty: 2 to 7 yr
Efficiency: 92%

Strengths

Cheapest entry point on the market
Acceptable performance for budget homes

Watch outs

Shorter warranty than rivals
Less engineer familiarity, repair lead times longer

Brand-by-type recommendations

Use case	Pick	Why
Best combi overall	Worcester Bosch Greenstar 4000	Reliability and parts availability, with a long warranty through an accredited installer. Hard to go wrong.
Best premium combi	Viessmann Vitodens 200-W	Up to 98% ErP efficiency and the best build quality here. Warranty is 7 years as standard, so budget for the paid upgrade if you want 12.
Best value combi	Ideal Logic Max	Ten-year warranty, compact, well under £1,000 supply. Strong choice for budget installs.
Best system	Vaillant ecoTEC plus	Quiet, efficient, easy to service. Excellent fit for 2-bathroom homes.
Best conventional	Worcester Bosch Greenstar Ri	Long-life cast-iron heat exchanger heritage. Ideal for older properties.

Recommendations are general and not endorsed by any manufacturer. Always confirm fit with a Gas Safe engineer.

Combi-only deep dive

For combi-specific brand data with model-level pricing and conversion guidance, see our dedicated sister site CombiBoilerCost.com.

FAQ

Which boiler brand do plumbers recommend?
In our experience Worcester Bosch and Vaillant come up most often, mainly because parts are stocked at every plumbers' merchant and the diagnostic tools are standardised. Viessmann is the connoisseur's choice but harder to source parts for outside major cities. We are describing how widely these brands are fitted and supported, not reporting a league table from a survey we can point you at. What installer familiarity really predicts is not which boiler is technically best, it is how easy and cheap your boiler will be to repair in year 8.
Is Worcester Bosch worth the extra cost?
The supply premium over Ideal or Baxi is roughly £200 to £400. For that you get a very well supported parts network, a warranty that runs to 12 years on the Greenstar 8000 through a Worcester accredited installer, and the most familiar diagnostic flow for whichever Gas Safe engineer turns up in year 8. Worth knowing that Ideal matches those 12 years on the Vogue Max, so Worcester is not alone at the top. For most homeowners staying in the property 10+ years, the premium pays back in lower repair friction rather than in warranty length.
Which boiler has the longest warranty?
Twelve years is the ceiling, and only two routes get there without paying extra: the Worcester Bosch Greenstar 8000 fitted by a Worcester accredited installer, and the Ideal Vogue Max. Note that it is the Vogue Max, not the cheaper Logic Max, that carries Ideal's 12 years: the Logic Max is 10. Viessmann starts the Vitodens 200-W at 7 years and sells a chargeable upgrade to 10 or 12. Vaillant tops out at 10 on the ecoTEC plus through an Advance installer, Baxi 10 on the Platinum, Alpha 2 to 7. Every one of these long warranties is conditional: register within 30 days, fit the manufacturer's specified system filter, and have it serviced annually. Miss any of those and Baxi, for instance, drops you to 2 years.
Are cheap boilers a false economy?
Not necessarily. An Ideal Logic Max combi carries 10 years when it is registered inside 30 days and serviced annually, and fitted by a competent Gas Safe engineer it will usually see that out. Where cheap boilers fall down is at the very budget end (sub-£500 supply): shorter warranties, fewer parts, and engineers less familiar with diagnostics. The mid-range from established UK brands is the value sweet spot.