When it comes to choosing the best boiler many people in the UK go for Worcester or Vaillant. Both companies are household names in the UK, being leading producers of high quality and reliable boilers.

The two firms have established an excellent reputation for delivering energy efficient appliances to UK residents and their ability to provide high-end heating and hot water performance. There is no doubt both offer quality products, but the question many people ask when considering buying a new boiler is which one is better than the other?

The purpose of this article is to compare the two market leaders while giving you the option of choosing which one is best for you. Before buying a new boiler, it is highly recommended you seek expert advice on the specification that meets your needs.

Brief Overview of Vaillant and Worcester

Vaillant is a German family company established more than 140 years ago. Though Vaillant boasts German design, all their boilers are manufactured in the UK, and replacement parts are easily available.

Worcester Bosch on the other hand, started as an independent business in Worcester, England, in 1962. In 1992, the company joined the international Bosch Group. The firm holds the Royal Warrant to supply heating products to the Royal Family.

Comparing the Specification of Both Brands

To effectively compare the brands we will pick one product from each – a 25KVA gas Combi boiler. The flagship we will use is the Vaillant ecoTEC series and the Worchester Greenstar series.

The output power(in kW) of the ecoTEC ranges from 32, 35, 38 while the Greenstar series ranges from 30, 34, 38, 42. The ErP rating of the EcoTec is A (89.4%) while that of Greenster is A (93%).

Similarly, the size (HxWxD) of the EcoTec is 72x44x34cm compared to the Greenstar at 71x40x33cm. The hot water flow rate (litres/min) of the EcoTec is 9.4 and 10.2 for Greenstar.

Both are LPG compatible, but the ecoTEC comes with a 5-year warranty (extendable up to 10 years at an additional cost), and the Greenstar also has a 5-year warranty (extendable up to 10 years if installation meets certain conditions).


The price for both models varies depending on which supplier you choose. However, Vaillant is a bit more expensive than Worcester Bosch but well worth the price due to its robust quality. The average price of a Greenstar is within the range of £750 – £875 while a Vaillant ecoTEC costs about £1000 – £1050.

Final Verdict

Considering all the factors and individual needs, my verdict would favour the Vaillant boilers.