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Worcester Bosch Combi Boilers: Reviews and Buying Guide (2020)

When people think of boilers, there’s usually one brand that pops into their head; Worcester Bosch. And in this quick guide, we’ll link out to reviews, show prices, and let you know what we think of Worcester’s combi boilers.

Worcester Bosch combi boilersWorcester combi boilers are by far the most popular brand in the UK. And, their success has led to the company employing over 2,000 people.

Part of the reason is the fact all their combis are A rated for efficiency, and come with a 5-year warranty as standard.

On many Worcester products, this can be extended to 10 years using an accredited installer, and a Worcester system filter and clock. One of the biggest installers of Worcesters, are HEATABLE. They’re a strong online comparison site for boilers, so are able to offer some of the most competitive prices around. You can get a fixed price on-screen in less than two minutes here.

Which Worcester Combi Boiler Do You Need?

Buying a combi boiler is confusing. Different Worcester boilers will suit different properties. The type of combi boiler a property will require depends on factors such as:

  • Number of bedrooms
  • Number of bathrooms
  • Number of radiators
  • Demand for hot water (i.e. the number of taps and showers on at the same time)

Please only use this table as a guide. A qualified Gas Engineer will be able to work out the correct boiler for your property, and should be consulted before making a purchase.

Alternatively, this 90-second form doesn’t just recommend the perfect boiler, but gives you a fixed price online too.

We’ve also included links to the relevant Worcester boiler reviews.

Model Heating Output (kw) Flow Rate for hot water (lpm) Suitable Property
25I 24kw 10.2 Smaller properties  with 1-3 bedrooms and 1 bathroom.Read our 25I review here.
30I 24kw 12.3 Medium-large properties with 3-4 bedrooms and 1 bathroom.

Read our 30I review here.

25SI Compact 24kw 10.2 Smaller properties  with 1-3 bedrooms and 1 bathroom.


The Compact is usually used when installation needs to take place in a small area, such as a kitchen cupboard.

30SI Compact 24kw 12.3 Medium-large properties with 3-4 bedrooms and 1 bathroom.


The Compact is usually used when installation needs to take place in a small area, such as a kitchen cupboard.

28CDI Compact 24kw 14.7 Medium-large properties with 3-4 bedrooms and 1 bathroom.
32CDI Compact 24kw 13.1 Medium-large properties with 3-4 bedrooms and 1-2 bathrooms.


Read our take on the 32CDI Compact here.

36CDI Compact 24kw 14.7 Medium-large properties with 3-5 bedrooms and 1-2 bathrooms.
29CDI 30kw 12.3 Medium-large properties with 3-5 bedrooms and 1-2 bathrooms.
34CDI 30kw 14.3 Medium-large properties with 4-5 bedrooms and 2 bathrooms.
38CDI 30kw 16.4 Large properties with 4-6 bedrooms and 2 bathrooms.
42CDI 30kw 17.2 Large properties with 5-6 bedrooms and 2-3 bathrooms.


Types of Worcester Combi Boilers

Worcester have created several ranges of combi boiler to suit several types of properties. Within these ranges, they have boilers with different central heating and hot water outputs.

Below is a guide to what each of the 4 ranges are suitable for.

Worcester Greenstar I

The Greenstar I is the most popular range in the Worcester line-up. Typically, properties using a 25I or 30I don’t have a particularly high demand for hot water or central heating output. For instance, typical 3-4-bedroom semi-detached houses with just 1 bathroom.

Worcester Greenstar SI Compact

As you can see from the heating and hot water output in the table above, the 25SI and 30SI match the 25I and 30I.

Essentially, they are used on boiler installations where efficient use of space is paramount. For example, a 25I might be installed in a garage, whereas a 25SI is going to be the top choice when it comes to boiler installation in a kitchen cupboard.

Worcester offer both Gas & LPG SI boilers.
Worcester Bosch CDI range

Worcester Greenstar CDI Compact

When the power of the SI just doesn’t cut it, but the installation area is still extremely small, the Greenstar CDI Compact is going to best option. There are three sizes including the 28CDI Compact, 32CDI Compact and the 36CDI Compact.

Like the SI, the CDI Compact is available in 2 setups; natural gas and LPG.

Worcester Greentstar CDI Classic

If you’re looking for a Worcester combi at the top-end with exceptional heating and hot water output, the CDI Classic is where you’ll want to focus your attention.

Worcester offers a 29CDI, 34CDI, 38CDI and 42CDI; so, there’s a range of options depending on the size of your property.

Typically, these boilers are either used in large houses where the demand for hot water is extremely high (i.e. lots of radiators, or multiple bathrooms).

Again, natural gas and LPG models are available.

Worcester Combi Boiler Prices

Combi Boiler Model Price (Boiler Only)
Greenstar 25I £950
Greenstar 30I £1,100
25SI Compact £1,100
30SI Compact £1,175
28CDI Compact £1,150
32CDI Compact £1,250
36CDI Compact £1,400
29CDI £1,200
34CDI £1,300
38CDI £1,400
42CDI £1,700

Worcester are by no means the cheapest brand available. Worcester boiler prices will vary anywhere from £800-2,000 for a combi. This price is without installation.

Typically, boiler prices including installation will start at around £1800 (for a budget boiler) and be as high as £3,500. Worcester installations tend to start in the region of £2,000.

However, HEATABLE have the best deals on Worcester Bosch boilers. And, that means they can offer installations as low as £1,770, with the option of finance. Quotes take around 90 seconds, and you can get yours here.

Worcester Bosch Greenstar i from Heatable

Remember, the price of a Worcester boiler isn’t all that needs to be accounted for. Most heating systems will need a new filter, clock, flue, flue extensions and a full system drain down and flush. All of this adds lots of time, and increases the price of the installation.

Worcester Combi Boiler Alternatives

Worcester have always had competition from a range of brands. Some of the most popular include Baxi and Vaillant. Of course, there are budget brands out there such as Glow-Worm and Vokera. The budget brands tend to appeal to a different market.

A boiler brand that is hot on the heels of Worcester right now is Ideal. Ideal Boilers give customers a similar (and in many cases, longer) warranties, and they usually blow Worcester boiler prices out of the water.

Installation of an Ideal boiler can be anywhere from £100-400 cheaper than the equivalent Worcester combi.

Currently, Ideal Boilers offer 3 ranges:

  • Logic (or, Instinct) inclusive of a 2-year warranty
  • Logic Plus, inclusive of a 7-year warranty
  • Ideal Vogue, inclusive of a 10-year warranty

Before installing a Worcester boiler, speak to your local Gas Engineer and try to get two quotes. They’ll also be able to advise which boiler is better suited to your property.

Or just jump here and get a fixed price on screen.

Worcester Boiler Service Cost

With anything mechanical, the cost of a service is something worth taking into consideration. Luckily, most combi boilers cost the same to service. The cost of a Worcester service should be in the region of £65-90.

The cost of the boiler service will depend on a few things:

  • Access
  • Type of boiler
  • Location

Finding Cheap Worcester Combi Boilers

One of the cheapest ways to get a Worcester combi boiler installed, is via HEATABLE. Streamlined sales helped them get Worcesters at low prices, and passing on those savings directly to you.

There’s a range of options on offer. All you need to do, is to fill out this 2 minute clickable form, and you’ll get your fixed price on screen; you won’t even need to put any personal details in, until you want to make a purchase.

What’s Next?

Hopefully this article has given an overview of the different Worcester combi boilers, prices, alternatives and where to find them at the cheapest possible price.

Remember, always consult a qualified Gas Engineer before making a purchase.

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