How do the main boiler brands compare?

Around a dozen manufacturers account for almost every new gas boiler fitted in Britain. The table compares them on the things that are documented and checkable: who owns them, where their popular ranges sit, the guarantee length available and the price tier. Guarantee figures are the maximum the manufacturer advertises and nearly always depend on conditions, which we come to below. Supply-only prices for a 24-30 kW combi are typical trade-merchant bands in 2026, before installation.

Brand Owner (country) Popular UK ranges Guarantee available Supply-only price tier (combi)
Worcester Bosch Bosch (Germany); made in Worcester Greenstar 2000, 4000, 8000 Life and Style Up to 10 years (4000), up to 12 years (8000) via accredited installer with system filter Mid to premium: roughly £1,000-£2,000
Vaillant Vaillant Group (Germany) ecoFIT pure, ecoTEC pro, ecoTEC plus, ecoTEC exclusive 2-5 years standard; up to 10 years through Vaillant Advance installers with protection kit Mid to premium: roughly £850-£1,700
Viessmann Viessmann Climate Solutions, part of Carrier (Germany/USA) Vitodens 050-W, 100-W, 111-W, 200-W 10 years (050-W, 200-W), 12 years (100-W), subject to registration Mid to premium: roughly £800-£1,600
Ideal Groupe Atlantic (France); made in Hull Logic+, Logic Max, Vogue Max 7 years (Logic+), 10 years (Logic Max), 12 years (Vogue Max) Budget to premium: roughly £800-£1,500
Baxi BDR Thermea (Netherlands); made in Preston Baxi 200, 400, 600, 800 2, 5, 7 and 10 years by series Budget to mid: roughly £650-£1,200
Glow-worm Vaillant Group; made in Belper Compact, Energy, Ultimate3 5 years standard; up to 10 years via Club Energy with Power Filter Budget to mid: roughly £650-£1,100
Alpha Immergas (Italy) E-Tec, E-Tec Plus, Evoke 7 years (E-Tec, Evoke), 10 years (E-Tec Plus) Budget to mid: roughly £600-£1,000
Vokera Riello / Carrier (Italy/USA) Easi-Heat Plus, Evolve, Vision 5-7 years depending on model Budget: roughly £600-£850
Potterton BDR Thermea; sister brand of Baxi Assure, Gold, Titanium 5-7 years depending on model Budget to mid: roughly £650-£1,000
Main BDR Thermea; sold mainly through merchants Eco Compact 5 years, subject to registration Budget: roughly £600-£750
Atag, Intergas, Navien Netherlands / Netherlands / South Korea iC range; Xclusive and Xtreme; NCB series Up to 10 years on selected models Mid: roughly £800-£1,300

Fitted, those tiers translate into roughly £1,800-£2,500 for a budget-brand combi swap, £2,200-£3,200 for a mid-range model and £2,800-£4,500 or more for a premium boiler with the longest guarantee. The installer's labour, flue and extras make up the difference; our new boiler cost guide explains every line of a typical quote.

Which brands offer the longest guarantees?

Guarantee length is the most useful single measure of how much a manufacturer is willing to stand behind a model, and it is also the figure most often quoted loosely. Three points matter.

The headline is a maximum, not a default. Worcester Bosch's 12 years on the Greenstar 8000 range requires a Worcester Accredited Installer and a Greenstar system filter; fitted by someone else, the same boiler may carry five. Vaillant's ecoTEC plus comes with five years out of the box and reaches ten only through a Vaillant Advance installer who fits the brand's protection kit. Baxi's 800 series drops from ten years to two if the supplied magnetic filter is not fitted and maintained.

Registration and servicing are conditions, not formalities. Almost every manufacturer requires registration within 30 days of installation and an annual service by a Gas Safe registered engineer for the guarantee to stay valid. Miss a service and many terms revert to one or two years. Our guide to boiler warranties goes through the small print brand by brand.

Check what is covered. Some guarantees are parts and labour for the full term; others give a longer period on the heat exchanger alone, such as Ideal's Logic+ with seven years overall and ten on the heat exchanger. A "lifetime" or 14-year heat exchanger promise is not the same as a 14-year boiler guarantee.

Ranked purely on the longest guarantee currently advertised for a homeowner model, the leaders are Worcester Bosch Greenstar 8000, Ideal Vogue Max and Viessmann Vitodens 100-W at 12 years, followed by a large group at 10 years: Worcester Greenstar 4000, Vaillant ecoTEC plus and exclusive, Viessmann 050-W and 200-W, Ideal Logic Max, Baxi 800, Glow-worm Ultimate3 and Alpha E-Tec Plus.

How do the brands compare on price?

Boiler makes in the UK fall into three loose price tiers, and the gap between tiers is usually a few hundred pounds on the appliance itself.

  • Premium (roughly £1,100-£2,000 supply only): Worcester Bosch Greenstar 8000, Vaillant ecoTEC plus and exclusive, Viessmann Vitodens 100-W and 200-W, Ideal Vogue Max. You pay for longer guarantees, higher modulation ratios, quieter running and, on some models, stainless steel heat exchangers and better controls.
  • Mid-range (roughly £800-£1,300): Worcester Greenstar 4000 and 2000, Vaillant ecoFIT pure, Viessmann 050-W, Ideal Logic Max, Baxi 800, Glow-worm Energy and Ultimate3, Alpha E-Tec Plus. For most three and four-bedroom homes this is the value sweet spot, with 7-10 year guarantees.
  • Budget (roughly £600-£850): Baxi 400 and 200, Main Eco Compact, Potterton Assure, Vokera Easi-Heat Plus, Glow-worm Compact, Alpha E-Tec. Guarantees of two to seven years and simpler controls, but the big-group models share parts and support with their pricier siblings.

The installed price matters more than the box price, and it varies by region and job far more than by brand. Model-by-model figures are in our boiler prices by brand guide.

Which brands are easiest to get parts and engineers for?

A boiler is only as good as the engineer who can fix it on a January morning. Here the large manufacturers have a structural advantage that no small brand can match.

Worcester Bosch, Vaillant, Ideal and Baxi (with Potterton and Main) have the largest shares of the UK market, so spare parts for current and recent models are held by national merchants and most independent engineers carry common items in the van. Glow-worm benefits from Vaillant Group logistics, and Viessmann has grown its UK parts stock and trained-installer base substantially over the past decade.

Smaller brands, including Alpha, Vokera, Atag, Intergas and Navien, make perfectly sound boilers, but a less common part may have to be ordered, which can mean an extra day or two without heating. Their installer networks are also thinner in some regions, so it pays to ask a local engineer which brands they fit and service regularly before you commit.

Each major brand runs an installer scheme that unlocks the longest guarantee: Worcester Accredited Installer, Vaillant Advance, Ideal Max Accredited Installer, Baxi Works, Glow-worm Club Energy and Viessmann Trained Installer. Using a scheme member is usually the simplest way to get the full guarantee and a technician who knows the model.

What do the individual brands offer?

A quick list of boiler manufacturers and where each one sits, with a link to the full review where we have one.

Worcester Bosch

The UK market leader, built in Worcester since the 1960s and part of Bosch since 1992. The Greenstar 4000 is the mainstream combi, the 8000 Life and Style are the premium models with outputs up to 50 kW, and the 2000 is the entry point. Strong points are the installer network and the 10-12 year guarantees; the trade-off is price. Full details in our Worcester Bosch boilers review.

Vaillant

German-engineered and the other half of the UK's premium duopoly. The ecoTEC plus is the long-running flagship with a wide modulation range; the ecoFIT pure is the lower-priced option with a shorter standard guarantee. Vaillant controls (sensoCOMFORT, vSMART) are well regarded. See the Vaillant boilers review.

Viessmann

Known for stainless steel heat exchangers across the range, including the budget-friendly Vitodens 050-W, and for a 12-year guarantee on the 100-W. The 200-W is a premium model for larger homes. Our Viessmann boilers review looks at the ranges in detail.

Ideal

Hull-built and the brand many installers reach for on price-conscious jobs without dropping to a budget tier. Logic+ (7 years), Logic Max (10 years) and Vogue Max (12 years) cover budget to premium. Read the Ideal boilers review.

Baxi, Potterton and Main

Three BDR Thermea brands made in Preston. Baxi's 200/400/600/800 series map neatly onto 2/5/7/10 year guarantees, Potterton is sold through merchants and heating contractors, and Main is the entry-level range. Our Baxi boilers review and Potterton and Main boilers review cover them.

Glow-worm

Vaillant Group's value brand, built in Derbyshire. Energy and Ultimate3 are the mainstream models with up to 10 years through Club Energy; Compact is the budget option. See the Glow-worm boilers review.

Alpha, Vokera, Atag, Intergas and Navien

Alpha (Immergas) competes on price with 7-10 year guarantees; Vokera (Riello) sells mainly through merchants with 5-7 years; Atag and Intergas are Dutch brands with a reputation among engineers for simple, robust designs; Navien is a Korean manufacturer newer to the UK. Our Vokera boilers review and our guide to Alpha, Atag, Intergas and other lesser-known brands have more.

Which boiler brands should you be cautious about?

Searches for "boiler brands to avoid" and even "Worcester Bosch boiler brands to avoid" come from a reasonable worry: that a cheap boiler will fail early and cost more in repairs than it saved. No major brand sold in the UK today is unsafe or unreliable as a class; every model must meet the same Gas Appliance and Building Regulations and be fitted by a Gas Safe registered engineer. The sensible caution is about tiers and terms, not names.

Be wary of a boiler when:

  • The guarantee is one or two years. A short guarantee on a budget model is not a scandal, but the saving over a five or seven-year model should be several hundred pounds to justify it. Baxi 200 and Vaillant's ecoFIT pure at its standard two years are examples where the registration route or the extra spend for a longer-guaranteed sibling is often worth it.
  • Your installer has never fitted the brand. Unfamiliarity leads to commissioning mistakes and slow diagnosis later. Ask what they fit most often.
  • Parts are slow or expensive. Ask a local engineer how quickly they can get a fan, pump or gas valve for that model. For discontinued ranges and brands that have left the UK market, the answer can be weeks.
  • The model is being sold off. End-of-line boilers can be good value, but confirm the guarantee is still the full term and that parts will be supported for ten years or more.
  • The price seems too good. An unusually cheap quote sometimes means an unbranded import, a grey-market unit without UK guarantee registration, or a boiler undersized for the house.

If you are replacing a boiler from a brand that no longer trades in the UK, the practical question is parts, not pride: once common components become unobtainable, repair stops being worth it and replacement is the realistic option.

Which boiler brand should you choose?

Work down the list and stop at the first line that fits.

  1. You want the longest guarantee and plan to stay in the house: Worcester Bosch Greenstar 8000, Ideal Vogue Max or Viessmann Vitodens 100-W, fitted by a scheme-accredited installer. Budget £2,800-£4,500 fitted.
  2. You want a premium name without the top price: Worcester Greenstar 4000, Vaillant ecoTEC plus through an Advance installer, or Viessmann 050-W. Typically £2,200-£3,500 fitted with a 10-year guarantee.
  3. You want the best value for a three or four-bedroom home: Ideal Logic Max, Baxi 800 or Glow-worm Ultimate3 with the filter and registration done properly. Around £2,000-£3,000 fitted, 10 years.
  4. You are on a tight budget and the home is small: Baxi 400 or 600, Alpha E-Tec, Main Eco Compact or Potterton Assure from a big-group manufacturer, £1,800-£2,500 fitted, accepting a 5-7 year guarantee.
  5. A local engineer you trust specialises in one brand: choose that brand within the tier you can afford. Their familiarity is worth more than a marginal spec difference.

Whatever brand you land on, match the model to your home's hot water needs first. The specific combi and system models we would shortlist for each house size are in our guide to the best combi boilers in the UK.

Frequently asked questions

Which boiler brands are made in the UK?

Worcester Bosch builds its Greenstar range in Worcester, Ideal makes Logic and Vogue boilers in Hull, Baxi and Potterton boilers come from Preston and Glow-worm manufactures in Belper, Derbyshire. All four are owned by larger European groups (Bosch, Groupe Atlantic, BDR Thermea and Vaillant Group respectively), but design, assembly and technical support for the UK market are based here, which helps with parts and engineer familiarity.

Are German boiler brands better than British ones?

Vaillant and Viessmann are German-owned and Worcester Bosch is part of the German Bosch group, and all three sit in the premium tier with long guarantees and strong engineer support. That does not make British-built Ideal or Baxi boilers inferior: their top ranges also carry 10-12 year guarantees. Judge a brand on the guarantee for the specific model, the installer network and parts availability rather than on the flag.

Which boiler brands should I avoid?

Rather than blacklisting names, avoid any boiler whose guarantee is short (one or two years) unless the price reflects it, any brand your installer has never fitted, and any model that is discontinued or whose parts are slow to obtain. Entry-level ranges from the big manufacturers are usually a safer budget choice than an unfamiliar brand, because the parts and support network behind them is the same as for the premium models.

Which boiler manufacturers offer the longest guarantee?

At the time of writing, 12 years is the longest widely available: Worcester Bosch Greenstar 8000 models through accredited installers, Ideal Vogue Max and Viessmann Vitodens 100-W. Several other ranges reach 10 years, including Baxi 800, Ideal Logic Max, Vaillant ecoTEC plus and Alpha E-Tec Plus. Every one of these depends on conditions such as registration within 30 days, a filter being fitted and an annual service, so read the terms before you buy.

Is a budget boiler brand a false economy?

Not necessarily. A five-year guaranteed budget combi from a major manufacturer, fitted well and serviced every year, can give good service and costs several hundred pounds less than a premium model. The economy turns false when the saving is small, the guarantee is very short, or the installer is unfamiliar with the brand. For most homes the sweet spot is a mid-range model with a 7-10 year guarantee.

Who makes Glow-worm, Potterton and Main boilers?

Glow-worm is the value brand of the Vaillant Group and shares engineering with Vaillant while being built in Derbyshire. Potterton and Main are sister brands of Baxi within BDR Thermea, and Main is sold mainly through trade merchants as an entry-level range. Buying one of these effectively gets you a budget model backed by one of the two largest manufacturer support networks in the UK.

Sources and further reading

Prices and scheme details were checked on 22 October 2026 and are shown as typical ranges. Always get written quotes from Gas Safe registered installers.