worcester bosch vs vaillant

Worcester Bosch vs Vaillant Boilers

The following in-depth, factual boiler comparison and review is about Worcester Bosch vs Vaillant and we will try our best, with the help of our in-house experts/engineers and installers with over 40 years experience, to give you all the information you need on both boiler brands and their best boiler offerings, so you as a consumer can make an informed decision about which brand you’d want to spend your hard earned money on.  Before we get started, let’s take a brief look at both brands.

Worcester Bosch vs Vaillant – Brand Reputation in the UK

worcester bosch vs vaillant

Before they were acquired by the German giant Bosch in 1992, they spent 30 years as Worcester, starting out as an independent business founded by Cecil Duckworth in 1962.  Over many years they have developed a brand reputation which is second to none in the UK market.  A lot of that is down to reliability, value for money and efficiency.  Brand affinity also plays a major part due to the Worcester name being British.  And because they’ve been active for so long, availability of parts and spares is no issue either.

worcester bosch vs vaillant

Vaillant are a family-owned business based in Germany, with their history dating back to 1874.  In 1894 Johann Vaillant patented a new “closed-system” gas-fired bathroom boiler (Source: Vaillant Wikipedia).  Vaillant have been operating in the boiler/heating industry for close to 140 years.

Both brands are well established in the UK, which means spare parts are not an issue.  Both brands also consistently feature in the “Best Buy Boiler” award given by a prominent consumer survey magazine in the UK.

Worcester Bosch vs Vaillant – Boiler Comparison

We will compare the best selling combi boilers from both brands.  We’ve chosen to do combi boilers for this boiler review and comparison post, because A) combi boilers sell the most.  And B) they are suitable for most of the properties.  There are even larger combis with a thermal store these days.  For this boiler comparison and review, we’re going to look at the following two combi boilers:

Worcester Bosch Greenstar 29CDi Classic Combination Boiler

worcester bosch vs vaillant

Key Features:

  • Highest hot water flow rate of the Greenstar combi wall mounted range.
  • Easy-to-use control knobs with easy-to-read temperature display.
  • Low energy pump reduces electrical usage.
  • Frost protection is included, reducing frost risk if installed in a garage or a loft.
  • Larger two bathroom properties can be supplied by higher output options.
  • Wide choice of controls enables greater comfort and economy.
  • Instantaneous hot water, always available.
  • Inbuilt keyless filling link making it easy to refill your system.
  • Large Condensesure style siphon built into the boiler – eliminates frost risk.


£1,114.70 inc. VAT (Boiler only merchant price. Excludes materials and installation costs)

Product Specification

Warranty (Years)5
Width (mm)440
Height (mm)750
Depth (mm)360
Weight (Kg)47.5
Output (Kilowatts)29
ErP Space Heating EfficiencyA
ErP Water Heating EfficiencyA
Flow Rate (L/min)12.3
FuelNatural Gas
MountingWall Mounted

And the competition…

Vaillant ecoTEC Pro 30 Combination Boiler

worcester bosch vs vaillant

Key Features:

  • Compact dimensions for flexible siting options.
  • Removable side panels and push-fit flue system – For improved accessibility, ease of installation and greater installation flexibility.
  • Highly efficient and economical to run – With up to an 89.3% efficiency rating (SAP 2009).
  • Quiet Mark accreditation and Which? Best Buy accredited.
  • Fully modulating low NOx burner and fan – For improved energy efficiency.
  • Built-in two-stage frost protection – To ensure optimal performance all year round.
  • Increased speed of hot water delivery – Thanks to Vaillant’s ‘aquaCOMFORT’ warm start feature.
  • Total system solution available from one manufacturer – Intelligent controls and accessories available.
  • Dedicated models available for LPG – Giving a solution for off-gas areas.
  • Wide modulation range of up to 1:4 – Ensuring low energy consumption and maximum efficiency.
  • Compatible with aroTHERM air-to-water heat pump hybrid system – Making the perfect entry into renewable systems.
  • Standard 2 year warranty, can be upgraded to a free 5 year warranty when registered through Vaillant Advance


£1,088.08 inc. VAT (Boiler only merchant price. Excludes materials and installation costs)

Product Specification:

Warranty (Years)5
Width (mm)440
Height (mm)720
Depth (mm)338
Weight (Kg)39
Output (Kilowatts)30
ErP Space Heating EfficiencyA
ErP Water Heating EfficiencyA
Noise Level (Decibels)49
Flow Rate (L/min)12.3
FuelNatural Gas
MountingWall Mounted

Worcester Bosch vs Vaillant – Warranty and Price

Both Worcester Bosch or Vaillant offer a standard warranty of 5  years, and extended warranties of up to 10 years, if installed by their approved installers.  Longer warranties are standard these days, as manufacturers compete with each other over warranty and price.  Please keep in mind though, even with a 10 year warranty, you do need to pay for an annual service of your boiler to preserve the manufacturer’s warranty.  Warranties can be extended sometimes at an extra cost.

Worcester Bosch vs Vaillant – Our Verdict

Before we give you the final results, like we said earlier in the post you can’t really go wrong with either boiler, as both of them are part of the trifecta of “Best Buy Boilers 2017” along with Viessmann by one of the largest consumer research brands in the UK.  Final comparison points below:

  • Worcester Bosch used to be cheaper, but Vaillant are now competing with them on price.
  • Both manufacturers now offer extended 10 year warranties if installed by an accredited/approved installer.
  • Both manufacturers have a wide range of boiler options, including compact models that fit in a cupboard.
  • Vaillant have a wall-mounted combi with thermal store compared to Worcester Bosch’s floor standing 440/550 CDi models.
  • In the “Best Buy” survey cited above, Worcester Bosch earned an overall rating of 92% with Vaillant coming in at 78%.
  • Vaillant is rated higher than Worcester Bosch for ease of service and repair.  Which means Vaillant boilers may be easier to maintain.
  • Vaillant has a stainless steel heat exchanger.

“OK tell us already!” – Honestly it’s a coin-toss between the two.  But we recommend Vaillant.  Even though Worcester Bosch are slightly more energy efficient and have a better brand reputation in the UK, the Vaillant wins simply because of having a stainless steel heat exchanger.  Whereas the Worcester Bosch has an aluminium heat exchanger inside it.  And we all know stainless steel is better than aluminium.

Worcester Bosch vs Vaillant – Is there a Third, Better Option?

Yes, there is.  If you’re in the market for a new boiler, may we suggest looking at Viessmann’s range of gas condensing boilers.  They were part of the 3 boiler manufacturers rated “Best Buy” in a UK consumer survey where more than 35,000 people were asked to describe their experience with their boilers.  And Viessmann, a relative newcomer to the UK market, was right up there.

worcester bosch vs vaillant, viessmann is better

Model Shown: Viessmann Vitodens 100-W

In our opinion the Viessmann Vitodens range trumps both Worcester Bosch and Vaillant.  Because they are a newer entrant into the UK market, some people often overlook them.  However they are the number one boiler company in Europe, especially Germany and have decades of commercial heating experience.  Include all of the features listed for Worcester Bosch vs Vaillant above, and add the ones below for Viessmann:

1. Patented Inox-Radial Stainless Steel Heat Exchanger. Manufactured in-house.

worcester bosch vs vaillant

  • All Viessmann boilers carry this heat exchanger.  Patented technology, it is unique to Viessmann, and it operates at an extremely high 98% efficiency with exceptionally safe and efficient operation.  And because it’s inox stainless steel, it’s highly corrosion resistant during its long service life.

2. 10 Years Warranty on Boiler and Heat Exchanger.

No surprise that Viessmann offers a 10-year guarantee against leaks resulting from corrosion on the stainless steel heat exchanger.

3. Price

Viessmann Vitodens 050-W – £870.44 inc. VAT

Viessmann Vitodens 100-W – £1,092.20 inc VAT

(Prices above are boiler-only merchant price. Excludes materials and installation costs)

The Viessmann 050-W is comparable to the Worcester Bosch and Vaillant models shown above.  The 100-W is a higher end model with stainless steel Matrix Cylinder Burner and 10 year warranty throughout.  Viessmann offer a more attractive price point because they manufacture most of their internal parts in-house.  Whereas other manufacturers source theirs from third party manufacturers.

4. Cylinder Burner and Thermal Stores made of Stainless Steel.

5. Combined PRV and Condensate Connection.

Installation is faster, simpler and more cost-effective as the pressure release valve (PRV) and condensate connection are combined, and long runs of additional piping are no longer required.

  • Fast and simple installation, saving time and expense.
  • Built in safety device meaning no discharge pipe for DHW cylinder is required.
  • No exterior PRV drip/stain as it feeds into a single cold water pipe.
  • One less pipe to penetrate the building fabric

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