Worcester Bosch Greenstar 30i Boiler Review

Company type: Manufacturer

HQ: Worcester, England

Founded: 1962

CEO: Carl Arntzen

The Worcester Bosch Greenstar 30i is a highly reliable combi gas boiler with a multitude of useful features. 30i is one of the most popular boiler models and can be found in many UK households. We reviewed it to tell you more about its advantages and different ways to improve your energy efficiency if you already own a Greenstar 30i.

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Is Worcester Bosch Greenstar 30i a good fit for your home?


The Worcester Bosch Greenstar 30i is a part of the Greenstar i range of lighter and smaller boilers. It is very compact and fits into airing cabinets, kitchens and utility rooms, which makes it a perfect solution for flats and small houses with limited space.

The Worcester Bosch Greenstar 30i has a maximum hot water output of 30 kW. A water output of 30kW can supply up to 15 radiators with hot water, so Greenstar 30i is a great solution for small to medium sized homes. It is an excellent choice for houses with 1-3 bedrooms and 1-2 bathrooms.

If you have a larger home, consider boilers with higher output levels, for example the Worcester Bosch Greenstar CDi range.

Below is a rough guide to what hot water output is recommended for different sized homes.

Property type No. of radiators No. of bathrooms Recommended hot water output
Flat or Small house Up to 10 1 24-27 kW
Medium house Up to 15 1 or 2 28-34 kW

Greenstar 30i

Large house 15-25 2+ 35-42 kW

Flow rate is another thing to consider when choosing a boiler, as this will affect the water pressure and temperature in your showers and taps. Greenstar 30i has a flow rate of 10.8 l/m, meaning 10.8 litres of water will pass through your taps or shower every minute. A flow rate of 10 and more litres per minute is acceptable, so Greenstar 30i’s flow rate is sufficient for homes with one or two bathrooms.

How energy efficient is the Worcester Bosch Greenstar 30i?


Worcester Bosch Greenstar 30i is 92% energy efficient, which puts it into the ‘A’ efficiency category. Having a high ERP (energy-related product) rating is very important, as it means your boiler wastes less fuel and requires less time to heat up your central heating and water. In financial terms, an ERP rating of 92% means that for every £1 you spend on energy to heat your home, 8p of that is lost to the heating process.

There are models on the market with better performance, for example, the Viessmann Vitodens 050-W 29kW, with energy efficiency of 97%.This is as good as boilers get today when it comes to energy efficiency.

Although Worcester Bosch 30i has a satisfactory ERP rating score that meets new boiler regulations, there is always room for improvement. Worcester Bosch Greenstar 30i is compatible with Greenskies solar panels that can help you reduce your energy bills by 60% as well as reduce your carbon footprint. To find out more about the right Solar hot water systems for your home, press the button below.

Find a Solar Thermal solution for your home

Improved energy efficiency when combined with wireless boiler controls

Worcester Bosch Greenstar 30i is compatible with Wave Smart Control, which is a wi-fi connected thermostat that allows you to regulate your heating with your smartphone or tablet.

Smart Control allows you to take advantage of its Weather and Load Compensating Features, which can boost your boiler's efficiency to an impressive 98 percent and help you save money on your energy costs.

Unlike many other thermostats on the market, the Wave thermostat takes into account the current room temperature and only fires the boiler at the necessary level (low, medium or full) to maintain your desired temperature, resulting in a far more efficient system. The Weather Compensating Feature will use your postcode to determine local weather conditions and regulate the temperature automatically to make sure your home stays cool during sunny days and cosy warm in winter.

Although Smart Control is highly reliable, if you’re experiencing issues with your wireless thermostat, click here for troubleshooting.

Key Features

Boiler that is easy to maintain and service

All of the Worcester Bosch Greenstar 30i’s components are serviceable from the front, meaning you don’t need to dismount the boiler from the wall to access its expansion vessel or break the combustion chamber to access the fan. This will make your engineer’s life easier when he comes in to fix issues and clean parts.

Give your boiler a service.

Make sure you don't invalidate your warranty. Call Smart Plan to get a boiler checkup to see if everything is in good working order.

OR 020 8146 3960

Enhanced protection against frozen condensate pipes

In winter times, frozen condensate pipes are one of the common problems people experience with their heating systems. In most households, the pipe used to remove acidic water is very thin and flows into the drain outside. When the pipe freezes, this will cause the condensate to back up into the boiler and may cause the whole system to fail.

Luckily, Worcester Bosch Greenstar 30i comes with a large condensate siphon to minimise this issue. The installed condensate discharge pipe is resilient to freezing up to -15 degrees. This feature will save you money and nerves in the long-term, as it is highly unlikely the pipe will require extra insulation or service visits.

Intelligent filling system

Worcester Bosch Greenstar 30i is fitted with a software programme that automatically adjusts water levels to ensure normal boiler pressure (between 1.0 and 2.0 bar) at all times. If the boiler's pressure is low, the internal filling valve will open and fill the heating system to the correct level. If there is a significant drop in pressure, suggesting a leak in the system, you will see an error code on the control panel.

Comes with a clear and informative LCD control panel

The Worcester Bosch Greenstar 30i has an easy-to-use four-button control panel that allows you to increase or decrease your central heating and hot water temperature. Heatronic control panel also features an all-improved interface, with text descriptions and error codes, enabling homeowners to detect faults and adjust settings more effectively.

Worcester Bosch Greenstar 30i Boiler Technical Specifications

Width 400 mm
Height 710 mm
Depth 330 mm
Weight 31.7 kg
Fuel type Gas
Display type Digital
Energy Efficiency Class A
Flow rate 10.8 L/min
Max kW output 30 kW
Sound power 50 dB
Standard Warranty 5 years

Alternatives to Worcester Bosch Greenstar 30i

In 2020, The Greenstar i range, which includes Worcester Bosch Greenstar 30i, was discontinued and replaced by the 4000 range. If you are looking for an alternative to the Greenstar i, the Greenstar 4000 boiler could be perfect for you. The new model comes with a higher efficiency rate, while keeping the benefits of compact size and easy-to-use controls. Read about the Worcester Bosch Greenstar 4000 here.

Still need help with your Worcester Bosch boiler?

Call Smart Plan and speak to our expert engineering team free of charge.

0333 772 6247