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Which Combi Boiler is Best? Worcester vs Vaillant

Worcester Bosch and Vaillant have been trusted by homeowners and heating engineers to provide reliable heating systems for a number of years.

To make choosing between these leading boiler manufacturers easier, we’re going to compare the key features of their best combi boilers: Worcester Greenstar 8000 Life vs Vaillant ecoTEC Plus.

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Comparing Worcester and Vaillant combi boilers

The combi boilers we’ll be comparing are the Greenstar 8000 Life 35 and Vaillant ecoTEC Plus 835 which both have an output rating of 35 kW. They run on natural gas but LPG conversion is available making them viable options for off-grid homes too.

Typically speaking, a 35 kW boiler is suited to properties with 3-4 bedrooms but you should always consult a Gas Safe registered engineer for their advice on the most suitable size boiler for the heating and hot water demands of your home.

Greenstar 8000 Life 35 vs Vaillant ecoTEC Plus 835

As combi boilers, neither of these boilers need to be installed alongside a hot water cylinder or any tanks in the attic. This is because they provide heating and hot water on demand by heating water directly from the mains. A number of other similarities are also shared by the Greenstar 8000 Life 35 and Vaillant ecoTEC Plus 835.

Manufacturer Worcester Bosch Vaillant
Combi boiler model Greenstar 8000 Life 35 ecoTEC Plus 835
ErP Rating A A
Seasonal Space Heating Efficiency 94% 94%
Maximum DHW Flow Rate 14.3 litres per minute 14.3 litres per minute
NOx Emissions Class 5 (Best) Class 5 (Best)
Standard Warranty 5 Years 5 Years
Extended Warranty 10 years when installed by a Worcester Bosch accredited installer Vaillant Advance installers can offer extended warranties of 7 or 10 years
Available Output Ratings 30, 40, 45 & 50 25, 32 & 38
LPG Convertible? Yes Yes
Dimensions (HxWxD) 780 x 440 x 365mm 720 x 440 x 372mm

Features and benefits

Both the Greenstar 8000 Life and Vaillant ecoTEC Plus have a number of features that can benefit your home.

Worcester Bosch Greenstar 8000 Life 35kW Combi Gas Boiler

  • As well as being available in the conventional white, Greenstar Lifestyle boilers are also available in black
  • Modulation ratio of 1:10 for increased efficiency
  • Wireless compatibility with the Bosch EasyControl allows you to control the heating from anywhere
  • Perfect replacement for the Greenstar CDi Classic as all pipe connections and fitting points are in the same location

Vaillant ecoTEC plus 835 35kW Combi Gas Boiler

  • Backlit display with user-friendly push button controls.
  • A stainless-steel heat exchanger that helps to deliver high fuel efficiency and increases lifespan
  • So quiet during operation that it has been awarded Quiet Mark accreditation
  • Range of heating controls to choose from, including the vSMART™ thermostat and smartphone app
  • Hot water delivery within 5 seconds and there’s no need for a hot water storage cylinder
  • Built-in frost protection which will protect the boiler during the cold winter months

Find out how the Vaillant ecoTEC Plus fared against the Viessmann Vitodens 050-W in Which is the Best Combi Boiler? Vaillant vs Viessmann.

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Get to know the brands

Worcester Bosch and Vaillant are two of the leading UK boiler manufacturers, delivering homes with reliable and efficient heating systems.

Worcester became part of the Bosch Group in 1996 after being originally founded in 1962. Armed with more than 50 years experience in the industry, Worcester Bosch has become the leading UK boiler manufacturer. Vaillant has been manufacturing heating products for over 140 years and led the way in developing the very first combi boiler.

What heating controls are available?

Heating controls help to make boilers even more efficient by giving you greater control. And, in the case of the Bosch EasyControl and vSMART™ thermostat, you’ll be able to take control from wherever you are using your smartphone.

Bosch EasyControl Features vSMART™ Thermostat Features
Presence Detection knows when you’re not home and adjust to your daily routine Adapts to the heating habits of your home
Individual room control when paired with Bosch Smart Radiator Thermostats Set your heating to be at your ideal temperature for when you get home
Domestic hot water control can help you to save money there too If you go on holiday during cold weather, the thermostat will work to prevent the heating system from freezing over
Modulates the heating system for increased efficiency Monitors local weather conditions to set your boiler at the most suitable temperature
Installer can receive any error and maintenance messages via the HomeCom Pro Compatible with Amazon Echo and IFTTT (If This, Then That) technology
An ambient light behind the thermostat gives you a quick understanding of the current setting of the heating system Take control of multiple boilers from a single app (perfect for anyone with multiple properties)

Do Worcester or Vaillant offer the best warranty?

Both manufacturers have shown confidence in their respective combi boilers by making them available with lengthy warranty periods. As standard, both models have a 5 year warranty with the option to extend to as long as 10 years when installed by an installer accredited by the manufacturer.

During both warranty periods you’ll be covered by the manufacturers should it fail as a result of the manufacturing process.

How much do these combi boilers cost?

When it comes to cost, often the deciding factor in many comparisons, there isn’t too much between these combi boilers. The Worcester Greenstar is likely to be the more expensive, with a potential price tag of £1,300 – £1,500 while you might expect to pay £1,200 – £1,400 for a Vaillant ecoTEC Plus 835. So not very much in it at all.

These prices don’t take into account the cost of installation, which you will also need to factor into your thinking when considering a new boiler. All installers will have their own rates which will vary depending on a number of factors including the type of heating system and where you live. To get the best possible price for a boiler installation, we highly recommend comparing quotes from at least 3 Gas Safe registered engineers.

Worcester vs Vaillant: Which is the best combi boiler?

The Worcester Greenstar 8000 Life and Vaillant ecoTEC Plus combi boilers are very evenly matched. In terms of efficiency, warranty and price there isn’t much between them. Having to crown a winner is a tough one but we’re going to give it to the Vaillant ecoTEC Plus 838 thanks to the stainless steel heat exchanger which could lower the risk of issues developing and increase efficiency during operation.

It’s always important to get the expert opinion of a Gas Safe registered engineer before having a gas boiler installed. They’ll be able to make the best recommendation for your home in terms of output rating and type of boiler (your home might be better suited to a system or regular boiler over a combi).

Using Boiler Guide, you can get free quotes from up to heating engineers based in your area and you’ll be under no-obligation to accept any of them.

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