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Worcester Bosch Greenstar 30CDi Classic System Boiler – Review

Founded in 1962, Worcester Bosch is a popular choice in the UK’s boiler market after almost five decades manufacturing energy goods. Worcester Bosch’s range of highly efficient system boilers has become a household name on a national scale.

In this review, we’ll be taking a closer look at the Greenstar 30CDi system boiler, a highly efficient 30kW system boiler making it the perfect choice for large homes and apartments with open plan areas.

Will the Worcester Bosch Greenstar 30CDi be suitable for my home?

The 30CDi offers a larger heating output of 30kW, which is suitable for homes with 13 – 18 radiators, several bedrooms/bathrooms and a hot water cylinder with a 150 – 300l capacity. As the 30CDi requires a hot water cylinder, the flow rate to your showers and baths won’t change. Unfortunately, the 30CDi isn’t the best choice if you’d like to fit it in within a standard kitchen cupboard.


The 30CDi onboard controls include an on/off switch, temperature settings for hot water and heating, and a small LED display for faults. The control panel will give you the most basic control of your central heating system, so if you’d like to take full advantage of your boiler, you’d better off installing either a programmable or smart thermostat.

Worcester Bosch offers a range of controls which will enable you to schedule temperature changes, as well as setting your preferred room temperature. You could opt for a mechanical thermostat which gives you basic temperature controls, although you may risk wasting energy and the temperature settings could be inaccurate. It’s essential to have full (and precise) control of your boiler, which is why we recommend the Greenstar Comfort thermostat if you want to venture down the programmable thermostat route. If a smart thermostat is on your list and you’d like to update your central heating system, Worcester Bosch’s smart thermostat, the Wave, allows you to control your heating and set schedules from your smartphone.

The Wave, a lot like the Nest, is a self-learning device, which alters your heating schedules based on your temperature settings and schedule. With the installation of a smart thermostat, you would see an improvement in your energy usage (in the form of lower bills) and enhanced energy efficiency. The extra level of control is a huge plus side to the Wave.


Coming in at 760x440x360mm, the 30CDi isn’t designed for a kitchen cupboard. However, there are alternatives out there that are more suitable if space is at a premium. For system boilers, you’ll need to consider the space required for a hot water cylinder to be installed. If your flow rate is sufficient and you have no more than 3 bedrooms and 1 bathroom (with a shower or bath), you may be able to get a combi boiler installed instead, which doesn’t require a cylinder.


Worcester Bosch’s Greenstar boiler range come with a 5-year standard warranty for your peace of mind. If you decide to install with Hometree, we can offer an extended warranty of 10 years.

Energy Efficiency

The Greenstar 30CDi is one of Worcester’s most efficient system boilers with its high ErP rating of 92% (an A grade). Installing a boiler with a high ErP rating means that you will not only reduce your carbon footprint but also reduce your spend on energy bills.

Unsure what the ErP Directive is? The Energy-related Products directive tests all boilers and energy products to ensure that they are performing correctly and to the highest standard before they’re available for purchase. If a product fails to reach the standards set out by the ErP, the manufacturer of the boiler will need to take the necessary steps to update its product to bring up its quality and meet the ErP’s recommendations. You can read more about the ErP Directive here.


The Worcester Bosch Greenstar 30CDi Classic System boiler is an excellent boiler choice for households with a higher hot water demand due to its high efficiency and ability to supply enough hot water for over 13 radiators. Due to the attention to detail with the Greenstar boiler range The Greenstar boiler range has won the Which? Best Buy award for 7 years in a row, which is a sign of the quality of the Greenstar range and why they’re a popular choice for customers. It’s also highly unlikely that your boiler will break down if you have a Worcester boiler installed, and you should see a reduction in your energy bills.

 Worcester Bosch Greenstar 30CDi Classic System
ErP rating (energy efficiency)A (92%)
Size (HxWxD in mm)760x440x360
Heating output (kW)30
Standard warranty (years)5 (extended warranties available)
Other available sizes (kW)34

Which? Boiler Review

The consumer group Which? review each boiler on the market to find the most (and least) reliable boilers according to a survey completed by thousands of boiler owners. In each review, Which? supply a brand score percentage and star ratings for each category. Take a look at the Worcester Bosch Greenstar 30CDi Classic System rating below:

Which? Score 
Efficiency rating★★★★★
Brand reliability★★★★★
Brand customer score★★★★★
Ease of repair★★☆☆☆
Ease of service★★★☆☆
Availability of parts and spares★★★★★
Build quality★★★★★
Engineer recommendation★★★★★
Brand score86%

Boiler manual

Worcester Bosch Greenstar 30CDi Classic System boiler manual

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