If you are considering a new boiler and the Worcester Bosch Combi 28 CDI keeps coming up in your research, you are not alone. This Worcester Bosch Combi 28 CDI review covers everything you need to know before making one of the most important purchases for your home, from real-world performance and pricing to the pros and cons.
Whether you are a homeowner in Manchester, Leeds, or Birmingham, or a landlord managing a rental property across the North West, Yorkshire, or the Midlands, this guide will help you decide whether this boiler is the right fit for your property.
Is the Worcester Bosch Greenstar 28 CDI Worth the Hype?
The Worcester Bosch Greenstar 28 CDI is genuinely one of the most talked-about combi boilers on the UK market, and for good reason. Worcester Bosch has been making boilers in Britain since 1962, and the CDI range sits right at the heart of their popular Greenstar line. The Greenstar name is no coincidence either.
Worcester Bosch built the range around energy efficiency and eco-friendly performance, making it one of the most recognisable heating solutions in UK homes today.
The 28 CDI Compact version, in particular, has carved out a strong reputation because it manages to deliver solid heating and hot water performance in a surprisingly small package. It is A-rated for energy efficiency and holds an ErP (Energy Related Products) rating that confirms it meets the European Union’s energy labelling requirements.
For homeowners and landlords across the North West, Yorkshire, and the Midlands, that means real savings on gas bills without sacrificing comfort.
What Are the Key Specs of the Worcester Bosch Greenstar 28 CDI?
The key specs of the Worcester Bosch Greenstar 28 CDI make it well suited to smaller and medium-sized UK homes. Here is a breakdown of the most important technical details in plain English:
| Specification | Detail |
| Heat Output | 28 kW |
| Hot Water Flow Rate | 10 to 11.4 litres per minute |
| Energy Efficiency | 94% (A-rated, ErP) |
| Dimensions (H x W x D) | 690mm x 390mm x 280mm |
| Standard Guarantee | 5 years (extendable up to 10 years) |
| Fuel Type | Natural gas |
| Frost Protection | Built-in (activates below 8°C) |
| Suitable For | 1 to 3 bedroom homes, up to 2 bathrooms |
The 28 CDI Compact is noticeably smaller in depth compared to Worcester Bosch’s standard Greenstar i models. That makes it a practical choice for kitchens and airing cupboards where space is genuinely tight. If you have a small to mid-sized home with one bathroom and up to three bedrooms, this boiler is designed with your property in mind.
How Does It Perform Day to Day?
Day-to-day performance from the Worcester Bosch 28 CDI is consistently rated highly by homeowners across the UK. Customers on Trustpilot frequently praise the boiler for its quiet operation, the speed at which hot water is delivered, and the noticeable reduction in their monthly gas bills after installation. Worcester Bosch as a brand holds an impressive Trustpilot presence with over 50,000 reviews, and reviewers overwhelmingly describe their experience as positive.
The built-in frost protection is a practical benefit that should not be overlooked, particularly during the colder months in the North West and Yorkshire. If the temperature drops below 8 degrees Celsius, the pump automatically circulates water through the system to stop it freezing.
The boiler also features Worcester Bosch’s CondenseSure siphon, which offers frost protection down to minus 15 degrees Celsius for up to 48 hours.
How Much Does the Worcester Bosch Combi 28 CDI Cost?
The Worcester Bosch Combi 28 CDI typically costs from around £2,495 fully installed, depending on the complexity of the job and your location. As a unit on its own, the boiler retails at approximately £1,312 to £1,400 before installation costs are factored in.
It is worth noting that boiler installation prices vary based on factors like whether you are replacing a like-for-like combi boiler or switching from a different system, whether new pipework or flue extensions are required, and the overall condition of your existing central heating system. As a rough guide, here is how the CDI Compact compares to similar boilers on the market:
| Boiler | Unit Cost (Approx.) |
| Worcester Bosch Greenstar 28 CDI Compact | £1,312 |
| Vaillant ecoTEC Pro 28 | £1,034 |
| Potterton Titanium 28 | £959 |
The Worcester Bosch carries a higher price tag than some competitors, but it is backed by one of the strongest guarantees and after-sales support networks in the industry. For landlords in the Midlands and homeowners across Leeds or Manchester, the long-term value and reliability often justifies the additional investment upfront.
What Guarantee Does the 28 CDI Come With?
The Worcester Bosch 28 CDI comes with a standard 5-year guarantee, which can be extended to up to 10 years when installed by an accredited Worcester Bosch installer alongside a qualifying system filter. This is not a warranty you have to pay extra for.
Worcester Bosch refers to it as a guarantee, meaning all parts, labour, and call-out costs are covered at no additional charge should anything go wrong within the guarantee period. For landlords who need reliability and want to minimise unexpected repair costs, this level of cover is genuinely reassuring.
Pros and Cons of the Worcester Bosch Greenstar 28 CDI
Pros
- A-rated energy efficiency at 94%, which can meaningfully reduce your annual gas bills compared to an older, inefficient boiler
- Compact dimensions make it ideal for properties with limited cupboard or kitchen space, particularly useful in smaller terraced houses common across the North West and Yorkshire
- Up to 10-year guarantee when installed by an accredited installer with a qualifying filter, offering excellent long-term peace of mind
- Built-in frost protection activates automatically at low temperatures, protecting your system during cold UK winters
- Which? Best Buy Award winner for 10 consecutive years, a mark of consistent quality and reliability
- Over 50,000 Trustpilot reviews with overwhelmingly positive feedback on performance and reliability
- Hot water delivered within approximately 5 seconds, ideal for busy households and rental properties
- Low energy pump reduces energy consumption during operation
- Made in the UK, which supports domestic manufacturing and means spare parts are widely available
- Recommended by the Energy Saving Trust, confirming its green credentials
- Quiet operation consistently praised by homeowners in customer reviews
Cons
- Higher upfront cost compared to budget alternatives such as Potterton or some Vaillant models
- Flow rate of 10 litres per minute on the 28 CDI model is on the lower end, which can feel limiting if you have two showers running simultaneously
- Not suitable for larger homes with multiple bathrooms. A 32 or 36 CDI would be more appropriate in those cases
- Ease of repair scores lower than ease of use in the Which? survey, suggesting some repair jobs require a specialist engineer
- Extended guarantee requires an accredited installer and system filter, meaning not every installation automatically qualifies for the full 10 years
- Some customers report occasional after-sales delays when contacting Worcester Bosch directly
Is the Worcester Bosch 28 CDI Worth It?
The Worcester Bosch 28 CDI is worth it for the majority of UK homeowners and landlords who want a reliable, efficient, and well-supported combi boiler for a small to mid-sized property. Here is how to decide whether it is the right choice for your specific situation.
Choose the Worcester Bosch 28 CDI If…
- You live in or own a property with one to three bedrooms and up to two bathrooms in the North West, Yorkshire, or the Midlands
- Your home has limited space for a boiler, such as a small kitchen cupboard or an airing cupboard
- You want the reassurance of a long guarantee, particularly as a landlord who needs to manage repair risk across multiple properties
- You are replacing an old, inefficient boiler and want to reduce your gas bills with an A-rated, high-efficiency system
- You value a well-established, trusted brand with a strong UK presence, excellent aftercare, and widely available spare parts
- You want a boiler backed by genuine Which? Best Buy recognition and industry-leading customer satisfaction scores
Do Not Choose the Worcester Bosch 28 CDI If…
- You have a larger home with three or more bathrooms, where a 32 CDI, 36 CDI, or a different system boiler may be more appropriate
- You are working to a tight budget and are primarily focused on finding the lowest upfront cost, as there are cheaper alternatives on the market
- You regularly need high simultaneous hot water demand, for example two power showers running at the same time
- Your home has older radiators or pipework that have not been serviced or powerflush cleaned, as the boiler will perform best on a clean system
Get a Free Worcester Bosch Boiler Quote from Clever Energy Boilers
Ready to upgrade your heating system with the Worcester Bosch Greenstar 28 CDI? At Clever Energy Boilers, we make the process simple, transparent, and stress-free.
We provide expert boiler installation across the North West, including Manchester, Salford, and Bolton, throughout Yorkshire covering Leeds, Sheffield, Hull, and Huddersfield, and across the Midlands including Birmingham, Coventry, and Nottingham.
Whether you are a homeowner looking to cut your energy bills or a landlord who needs a reliable heating solution for your rental property, we are here to help.
Request your free, no-obligation boiler quote today and one of our friendly team will be in touch to walk you through your options, including installation costs, and finance options.
Frequently Asked Questions
Is the Worcester Bosch Combi 28 CDI Compatible with a Smart Thermostat?
Yes, the Worcester Bosch 28 CDI is compatible with a range of smart thermostats, including the Worcester Bosch Wave and several popular third-party options such as the Nest and Hive. A smart thermostat allows you to control your heating remotely via a smartphone app, which can lead to further energy savings on top of what you already gain from the boiler’s high efficiency. If you are having the boiler installed by Clever Energy Boilers, ask about smart thermostat options as part of your new installation.
How Long Does a Worcester Bosch 28 CDI Last?
A Worcester Bosch 28 CDI, when properly serviced once a year by a Gas Safe registered engineer, can last between 10 and 15 years or longer in many cases. Worcester Bosch’s own guarantee of up to 10 years reflects the brand’s confidence in the product’s longevity. Keeping on top of annual boiler servicing is the single most effective way to protect your investment and maintain peak efficiency over the boiler’s lifetime.
Does the Worcester Bosch 28 CDI Work with an Existing Magnetic Filter?
Yes, if your current central heating system already has a magnetic filter fitted, the Worcester Bosch 28 CDI can work alongside it. In fact, having a magnetic filter on the system is a requirement for qualifying for the extended Worcester Bosch guarantee period of up to 10 years. If your existing filter is in good condition, a Gas Safe engineer will flush and clean it as part of a proper installation, rather than necessarily replacing it.
Can the Worcester Bosch 28 CDI Be Installed in a Flat or Apartment?
Yes, the compact dimensions of the Worcester Bosch 28 CDI make it a practical choice for flats and apartments where both space and hot water demand are typically lower. Its small depth of just 280mm means it can sit inside a standard kitchen cupboard without needing any structural modifications in most cases.
Landlords with buy-to-let flats across the North West, Yorkshire, and the Midlands often choose the 28 CDI for exactly this reason.
What Is the Difference Between the Worcester Bosch 28 CDI and the 28 CDI Compact?
The Worcester Bosch 28 CDI Classic and the 28 CDI Compact share similar performance and efficiency ratings but differ primarily in size. The Compact version is smaller in depth, sitting at 280mm deep compared to 338mm for the Classic version. The Compact is designed specifically for tight installation spaces, while the Classic suits properties where cupboard depth is less of a concern.
Both carry the same A-rated efficiency and are available with the same extended guarantee terms.
- Market leading technology
- Space saving compact combi boiler
- ErP rating 93%
- Very eco friendly
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- Up to 10 years warranty
- Suits 1 to 2 bedroom home with 1 bathroom
- Keep warm instant hot water and heating
- Excellent Which? reviews
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