Heatable uses cookies to give users the best possible experience.

View Policy

Black Friday Boilers
We've knocked £100 off, everything.

COVID-19 Notice
We're still installing boilers, safely. Read more.

Worcester Bosch vs Vaillant Boilers - Which is Better?

When in the market for a new boiler, at some point it’s likely that you will stumble upon two of the UK's biggest brands – Worcester Bosch and Valliant.

Then, you'll no doubt be left thinking....Which to choose? Which is best? Which is a Which? Best Buy? Which should you choose - Worcester Bosch or Vaillant Boilers? 

In this post, we’ll be doing a deep-dive and comparing the most popular boiler models from each – the Worcester Bosch Greenstar and the Vaillant EcoTec.




Bosch vs Vaillant Test

First, who are Worcester Bosch, and whom are Valliant Boilers? 

Founded in the UK back in swinging 1962, Worcester Bosch has been a big name in the British boiler industry for decades, renowned for their high-quality build and excellent aftercare.

Check the latest deals on Worcester Bosch boilers here

Worcester Bosch Logo

In 1992, the company joined the German-based Bosch group and for the last 10 years have won the Which? Best Buy Award.


Then, there's Vaillant.

Vaillant Logo

Another German-based company with a 140-year history as a family-run enterprise.

Das ist gut, ya?

Although the brand offers German engineering and design, all of its boiler products are manufactured in the UK. This means parts are relatively easy to source and within a relatively short time frame. 

Quiet Mark Vaillant BoilersSimilar to Worcester Bosch, the brand has performed well on consumer award surveys. Notably, the brand was awarded Quiet Mark accreditation by the International Eco-Award Scheme, given to the quietest products.


Worcester Bosch Greenstar vs Vaillant EcoTec 

When comparing two popular boiler brands, it makes sense to make a comparison between two of their most popular boiler models.

The table below shows how two combi boilers, one from each manufacturer compare in terms of the warranty offered, power, efficiency and other important metrics. 

  Worcester-Bosch Greenstar 25i Vaillant EcoTec Plus 825
Standard Warranty 10-years through Heatable 5-years
Hot Water Flow Rate 10 Litres per min. 9.4 Litres per min.
ERP Rating A A
Smart thermostat compatible Yes Yes
LPG Compatible Yes Yes
Heat Exchanger Aluminium Stainless Steel
Shock Arrestor standard No No
Efficiency up to 94% 89.4%
Noise output (dB) 50 46

Warranties & Aftercare Comparison

Bosch vs Vaillant Aftercare/Warranty

Worcester Bosch is unique in that they do not simply offer a traditional warranty, but a no quibble guarantee. 

What’s the difference, you say?

A guarantee is superior to a warranty since it’s an agreement from the manufacturer that they will attend your property and repair or replace your boiler as soon as possible. 

You can check the latest price on Worcester Bosch boilers here

A conventional warranty (offered by most other brands) is a contract to investigate the issue, but not an unconditional agreement to repair the boiler free of charge.  

When purchased via Heatable, all Worcester Bosch boilers in the Greenstar Range come with a 10-year loooong guarantee.

Worcester Bosch 10 Year Guarantee

Valliant also offers a 10-year warranty (not a guarantee), but importantly, it’s only offered at an additional cost. Vaillant only offers a 5 year warranty as standard. 

Remember that your condensing boiler needs to be serviced annually and by an approved installer for the guarantees and/or warranty to remain valid. 

Learn all about combi boilers in our what is a combi boiler guide and see how Worcester Bosch fared against Baxi in our Worcester Bosch vs Baxi comparison. 

Price-Point Comparison

Worcester Bosch Greenstar vs Vaillant EcoTec 

Cost/Value Bosch vs Vaillant

Often the decision-maker when it comes to buying a new boiler – the price.

Being leading brands, neither brand is considered the cheapest, but for good reason. They are both trusted and reliable manufacturers. 

In terms of price, for a Greenstar 25i by Worcester Bosch you are looking to pay between £800 – £975 (that's boiler alone, without installation, flue, accessories or anything else), while a Vaillant EcoTec Plus 825 will cost between £1000 – £1100.

Worcester Bosch Boiler Cost

So, as you can see, on average a Worcester Bosch boiler is cheaper to purchase than a Vaillant boiler. 

Of course, boiler prices will vary depending on the supplier you choose.

However, Heatable offer a price match guarantee, see how much your new boiler will cost today using our boiler calculator tool. 

Some of the brands most recent and popular models include the 2000, 4000 and the 8000, you can read our full reviews of them:

Customer Trustpilot Reviews

Customer Service Vaillant Worcester

Awards from third party consumer organisations like which are highly credible, but nothing comes close to the honesty and reviews of everyday users of the product. 

Fortunately, Worcester Bosch has some of the best customer reviews on the TrustPilot platform and far better than any other boiler manufacturer at all. 

Worcester Bosch Reviews

Worcester Bosch has gained an incredible number of user reviews. As of January 2021, nearly 20,000 customers left a review.

The average rating of these reviews was 4.7 out of 5 stars, quite fantastic for a brand selling in such large volumes. Agree?

Vaillant has also performed extremely well when it comes to customer feedback. As of January 2021, they have amassed over 12,000 reviews on the platform. 

Vaillant TrustPilot Reviews

The average rating of Vaillant’s reviews was 4.6 (almost as good as Worcester, but not quite!), an obvious reflection of their products quality and the aftercare offered by their team. 

So in terms of reviews, the brands perform remarkably similarly. 


Size (Dimensions, not power)

Vaillant Bosch Smallest Boiler

Another important question all new boiler buyers commonly ask is.... will it fit in my cupboard?

A key question for those with limited space, we think you'll agree.

...jokes aside, size really does matter

Both the Worcester Bosch Greenstar and the Vaillant EcoTec are considered small boilers; on average Vaillant boilers are less wide.

However, Worcester does have the Worcester Greenstar CDi Compact, or Si Compact, designed specifically to fit into small spaces such as kitchen cupboards. 

Control Options

Vaillant Bosch Control Options

Both boiler brands provide their models with conventional, mechanical controls with 24-hour programming and digital controls that allow you to set a 7-day schedule.

Nest Smart Thermostat Bosch VaillantBoth brands offer the ability to utilise smart thermostats too, such as Hive and Nest, allowing you to control and schedule your boiler from the comfort and convenience of your smartphone. 

Other Notable Features...

Features of Worcester Bosch & Vaillant Boilers

Here are some of the best features offered by each of the brands. 

Some of Worcester Bosch’s most popular features include: 

  • Installed with the condenseSure siphon, offering boiler frost protection
  • A-rated boilers - efficiency rating of up to 99.5% when operating at 30% capacity
  • CDi compact ideal for smaller spaces
  • Built-in keyless filling link making it easy to refill your system
  • Low energy pump limits electricity usage
  • 10-year guarantee when purchased through Heatable
  • Excellent customer service and aftercare

Some of Vaillant’s most popular features include: 

  • Awarded QuietMark – an international award for quiet products
  • ErP A-rated boiler for heat
  • 5-year guarantee as standard (can be upgraded for additional costs)
  • Excellent customer service and aftercare

Worcester Bosch vs Vaillant Boilers: Our Verdict

Worcester Bosch or Vaillant

Although both Worcester Bosch and Vaillant are extremely well rated and reputable boiler brands, offering reliability, value and a superb choice for a variety of different hot water demands, we think Worcester has the edge. 


Bosch Boiler Best

On average Worcester Bosch boilers are typically slightly cheaper than Vaillant and everyone likes to save a little money.

Worcester Bosch also offers 10-year guarantee (not just a warranty) when purchased via Heatable, while Vaillant only offers a 5-year warranty as standard, which you can then upgrade for an additional cost. 

Worcester also has a brilliant range of boilers, in different power outputs and dimensions, for example, the Greenstar Compact, ideal for kitchen cupboards. 

Lastly, the brand has been a Which? Best Buy Award winner for 10 years running. Truly brilliant

Here’s a summary of why you'll probably want a Worcester:

  • Which Best Buy Award winner for 10 consecutive years
  • A 10-Year Guarantee, not just a “warranty”
  • Slightly cheaper than Vaillant
  • Readily available parts in the UK

Looking to buy a Worcester Bosch?

Order with Heatable, and we could be fitting your new boiler tomorrow.

Why choose Heatable? 

  • Gas Safe installation within 24 hours
  • Thousands of happy customers – an average score of 4.9 on Trustpilot (that’s better than the market leader)
  • Price match guarantee – if you find a cheaper quote, we will match (must be like for like)
  • Multiple payment options - interest-free available
  • 10-year guarantee
  • Fixed price guarantee – no hidden costs
  • Save your quote until later

Use this clickable form to get a fixed price on the screen instantly.

More advice

New boiler deals

Buy your new boiler, better

Get a fixed price on a Which? Best Buy in minutes

Heatable is registered in England and Wales No. 08804726 (VAT No. GB205805920 ). Trading address is 1 Station Road, Great Sankey, Warrington, Cheshire, WA5 1RH. Heatable acts as a credit broker (not as a lender) and offers credit products through a panel of lenders. Heatable is authorised and regulated by the Financial Conduct Authority (reference no. 805259).

[1] Price based on a like for like combi swap in a 2 bed, 1 bathroom terraced home with a standard flue

[*] Installation dates are subject to installer availability

[ยน] only available on combi boiler installations

Financial Support: If you are in receipt of certain benefits, you may be entitled to claim a free boiler grant.