Worcester Bosch Greenstar 4000 Boiler Review

Worcester Bosch Greenstar 4000 Overview

The Greenstar 4000 is designed for smaller homes where a combi boiler can provide heating and hot water without the need for a separate cylinder.

The original specifications state that the boiler operates on natural gas, has an A-rated ErP efficiency rating and is compatible with Worcester Bosch controls and smart products, including Nest, tado and Hive.

The boiler measures 710mm high, 400mm wide and 310mm deep. It can be suitable for installation in a kitchen cupboard, although the available space should always be measured before installation.

The Greenstar 4000 is hydrogen-ready, certified to run on a 20% hydrogen blend, confirmed by Worcester Bosch's own technical documentation and public statements from its product management team.

Is the Worcester Greenstar 4000 Right for Your Home?

The Greenstar 4000 is most suitable for small to medium-sized homes. As a combi boiler, it provides hot water on demand without requiring a separate hot water cylinder.

The right output depends on the size of the property, number of radiators and expected hot water demand. The 25kW model is aimed at smaller homes, while the 30kW version provides a higher hot water flow rate.

If your property has multiple bathrooms or higher simultaneous hot water demand, the boiler size needs more careful consideration.

If you're comparing the Greenstar 4000 with other combi models, our guide to the best combi boilers in the UK covers other options and what to look for.

Worcester Bosch Greenstar 4000 25kW vs 30kW

Worcester Bosch Greenstar 4000 25kW

The Greenstar 4000 25kW model has a stated heat output of 25kW and a flow rate of 10.5 litres per minute.

It is presented as an option for smaller homes with up to 10 radiators. For homes with greater hot water demand, the 30kW model may be more suitable.

Worcester Bosch Greenstar 4000 30kW

The Greenstar 4000 30kW has a higher power output and a stated flow rate of up to 12.3 litres per minute.

It's suitable for small to medium-sized homes and can meet higher hot water demand.

The exact output should be based on the property's heating and hot water requirements rather than radiator numbers alone.

Worcester Bosch Greenstar 4000 Key Features

A-rated efficiency

The Greenstar 4000 has an A-rated ErP efficiency certification for heating and hot water. It can modulate its output from 4.8kW up to 30kW, allowing it to adjust to changing heating demand.

Quiet operation

The Greenstar 4000 operates at around 45dB(A) and has Quiet Mark approval. Lower operating noise can be useful when the boiler is installed close to living or sleeping areas.

Smart controls

The Greenstar 4000 is described as compatible with Worcester Bosch controls and a range of smart heating products. These can provide more convenient control over heating and hot water.

Easy servicing access

The boiler has removable side panels to provide access for servicing and maintenance, along with straightforward installation and accessible components.

Intelligent filling system

An intelligent filling system is included as a Greenstar 4000 feature, designed to help maintain boiler pressure.

Simple Switch and Quick Tap

The Greenstar 4000 range includes features such as Simple Switch and Quick Tap.

Simple Switch is intended to make replacement of selected Worcester Bosch boilers more straightforward. Quick Tap is described as helping provide hot water more quickly when a tap is opened.

Worcester Bosch Greenstar 4000 Pros and Cons

Pros

• A-rated ErP efficiency.
• Available in 25kW and 30kW combi versions.
• Compact wall-mounted design.
• Quiet operation.
• Compatible with smart heating controls.
• Designed for straightforward servicing access.
• Suitable for many small to medium-sized homes.

Cons

The Greenstar 4000 is not designed to meet every property's heating and hot water requirements.

Larger homes with higher hot water demand may need a different boiler type or a higher-capacity system. Properties with several bathrooms should also be assessed carefully before choosing a combi boiler.

The 25kW and 30kW versions have different hot water outputs, so choosing between them should be based on the property's actual requirements.

What Is the ErP Rating of the Worcester Bosch Greenstar 4000?

The Worcester Bosch Greenstar 4000 has an A-rated ErP efficiency certification.

ErP stands for Energy Related Products. The rating system helps consumers compare the energy efficiency of heating appliances.

An A-rated boiler meets the required efficiency standards for its category. However, actual running costs will also depend on how the heating system is designed, controlled and used.

Worcester Bosch Greenstar 4000 Boiler Prices

Prices for the Greenstar 4000 range, including the 25kW and 30kW combi boilers, vary and have not been carried across as fixed current figures because boiler costs can change.

The final cost of a new boiler depends on the model, installation requirements, controls, flue arrangements and any additional work required at the property.

A like-for-like replacement can be more straightforward than an installation involving changes to pipework, flue arrangements or heating controls.

Professional Boiler Installation in London

Choosing the right boiler is only part of the installation. The boiler needs to be correctly sized, installed and commissioned for the property.

Serviceteam provides boiler installation in London and can advise on whether a Worcester Bosch Greenstar 4000 is suitable for your home.

A like-for-like replacement can be more straightforward than an installation involving changes to pipework, flue arrangements or heating controls.