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Worcester Bosch Greenstar 28CDi Compact Boiler Review

Worcester Bosch is arguably the UK's most well-known boiler brand, and with several boilers within their Greenstar range receiving the prestigious Which? Best Buy Award for 10 years on the trot, it is no surprise they continue to be a best seller.

Worcester Bosch Logo

You're sold. You've bought into the brand. But, your current boiler is housed in a tiny cupboard, and you think you're stuck.

Fear not, as Worcester's cracking engineers have the solution. The CDi Compact. And boy, isn't it compact.

Need to know the cost of a new boiler, quick? Find out what replacement you need along with costs (takes 60 seconds).


Worcester Bosch Greenstar 28CDi Compact Review 

Ranking in #1 in our top 10 list of the best boiler brands, Worcester Bosch is a household name in the UK when it comes to home heating and has been manufacturing boilers since the swinging '60s (1962 to be exact). 


Worcester Bosch Greenstar CDi Compact

Slotting into their ultra-efficient Greenstar range, the CDi Compact joins the popular Worcester Greenstar 25i and Worcester Bosch Greenstar 30i, but with a Danny Devito design, the CDi is suitable for those who're short on space.

Greenstar 28CDi Compact dimensions:

Height (CM) Width (CM) Depth (CM)
69 39 28

Standard Greenstar i's dimensions:

Height (CM) Width (CM) Depth (CM)
71 40 33

It's not quite as tall, it's not quite as wide, but it's significantly less deep which is key.

Note - you will need at least a 60 cm clearance area at the front for your annual service to be carried out

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

Read our in-depth Worcester Bosch Greenstar CDi Compact Review.

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

Greenstar 28CDi Compact: Range 

The Greenstar 28CDi Compact range is available in the following sizes (power outputs):

Hot Water Output Central Heating Output Flow Rate
28kW 24kW 10l/min
32kW 24kW 11.5l/min
36kW 24kW 12.9l/min

The Greenstar 28CDi Compact combi boiler has a heat output of 28kW and a flow rate of 10 l/min, making it suitable for small properties with a single bathroom. 

For comparison, the 32CDi Compact has a heat output of 32kW and a flow rate of 11.9l/min, making it suitable for medium-sized properties with multiple water outlets. 

While the 36CDi Compact has a heat output of 36kW and a flow rate of 12.9l/min, making it ideal for larger proper properties with multiple water outlets. 

If you haven't got a clue what any of the above means, call us on 0330 113 1333 and we'll be happy to help.

Want to know which boiler power is right for your home? Check out our what size boiler do I need guide.

Is your current Worcester Bosch boiler experiencing problems? Check our Worcester Bosch Boiler Faults guide for common issues and potential fixes. 

Which Greenstar 28CDi Compact model is right for your home?

To determine which Greenstar CDi Compact model is most suitable for your homes needs, use our free tool. It'll do all the hard calculating work for you, and give a fixed price.

The type of CDi compact that you'll need is based on several factors, but, to put it simply, if you've got a swanky home with many many bathrooms, you'll be needing a big boy.

Interested in paying for your boiler monthly? Check out our boilers on finance guide, for the full run down.

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

Greenstar 28CDi Compact: Warranty Guarantee Period 

Greenstar CDi Compact Warranty

When you're looking to purchase a new boiler, the warranty period is a major consideration.

Therefore, the goal is to secure a boiler at a great price that comes with a warranty period that lasts longer than your longest lasting milk.


Want an exact price on a new boiler? Use our boiler quote calculator (no personal details needed).

Worcester Bosch offers a 7-year guarantee as standard on their CDi compact range.

Yep, you read that right, Worcester is the only condensing boiler brand to offer a no quibble guarantee. Other brands offer a typical, predictable and sometimes worthless "warranty".

Buy your Greenstar CDi compact boiler through Heatable, and you'll get access to an exclusive 10 years parts and labour guarantee


Greenstar 28CDi Compact: Prices

If you purchase a Worcester Bosch boiler through Heatable, our fixed price offer includes both the boiler and complete installation. The latter being key.

Prices for the Worcester Bosch Greenstar Compact range begin at £2,095 and are available with 0% APR (over 2 years). Get your fixed price here.

Worcester Greenstar CDi Compact Price

Here's a quick overview of where the CDi compact sits in terms of price, against other options:

Model Type Warranty Which? Best Buy Prices (From)   
Worcester Bosch CDi Compact Premium 10 Years Yes £2,095
Alpha E-Tec Budget 10 Years No £1,545
Vitodens 050-W Standard 10 years Yes £1,745
Greenstar i Standard 10 Years Yes £1,850

Vitodens 100-W Premium 10 years Yes £1,995
Worcester 8000 Premium 10 Years Yes £2,395

As you can very well see, there are cheaper alternatives. But, the Worcester Bosch price tag is higher for a reason.

  • 10-year guarantees (not warranties)
  • Which? Best Buys
  • High TrustPilot ratings
  • Incredible aftercare and service
  • Huge brand name
  • Made in the UK

How much will a boiler installation cost? Check out our new boiler cost guide for the full rundown.

Greenstar 28CDi Compact: Efficiency

CDi Compact A-RatedCDi Compact A-Rated


When it comes to their green credentials, Worcester Bosch takes great pride in innovating and improving the heating industry.

They love their greens so much, that they even popped it straight into the name of their most popular range, the Greenstar.

Energy Saving Trust BoilerThis very range is Worcester Bosch’s ultra-efficient baby, boasting an efficiency rating of up to 99.5% when operating at 30% capacity, with the CDi Compact being an A-rated boiler. It also means they are recommended by the Energy Saving Trust, so you know they're good.

If you upgrade from an old G-rated boiler, you can potentially save hundreds of pounds a year on heating costs. That's right, hundreds of pounds. Not tens of pounds.

Want to have your boiler moved to a different location? Check out our cost of moving a boiler guide.

Read our Worcester Bosch vs Viessmann boilers review if you want a quick comparison of these two trusted boiler manufacturers. 

Boiler frost protection

During the colder, winter months, a common issue is a frozen boiler, particularly a frozen condensate pipe. This is by no means a serious issue (most of the time), but it can be a total nightmare on a cold and frosty morning, as your boiler would simply shut down.

To alleviate this common issue, the Worcester Bosch CDi Compact range has built-in frost protection. If the temperature falls below 8°C the pump will run to circulate water and prevent the system from freezing. 

The CDi Compact also comes equipped with their CondenseSure siphon, offering frost protection if the temperature drops below -15°C for up to 48 hours, which is adequate protection for the UK.

Learn all about combi boilers in our what is a combi boiler guide. 

You can check the latest deals on Worcester Bosch boilers here, and see how the brand compared to another market leader in our Worcester Bosch vs Vaillant Boilers post. 

Greenstar 28CDi Compact: Conclusion

If you are looking for a new boiler that's an energy-efficient, A-rated combi boiler that you want to install into a tight space, you needn't look any further.

Put. The. Google. Down.

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

Manufactured by a long-standing, award-winning boiler brand, and with an impressive 10-year guarantee, the CDi Compact is a worthy investment for the house proud.

To get the best price on a Greenstar CDi compact boiler, buy from Heatable.


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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.