Worcester Greenstar 4000 25 Combi Boiler

The Worcester Greenstar 4000 25kW Combi Boiler is one of the UK’s best-selling boilers, offering outstanding efficiency, quiet operation, and reliable hot water performance for small to medium-sized homes. Built on the success of the award-winning Greenstar i range, the 4000 delivers improved flow rates, modern styling, and upgraded controls—making it a perfect choice for homeowners seeking performance, comfort, and long-term reliability.

With compact dimensions and simple installation features, the Greenstar 4000 is an ideal replacement for older Worcester models and fits neatly into most standard kitchen cupboards.

Key Features

• 25kW combi boiler ideal for small–medium homes

• Improved hot water flow rate of up to 10.2 L/min

• A-rated efficiency for reduced energy bills

• Ultra-quiet operation, suitable for installation in living spaces

• Modern, sleek Worcester Bosch design

• Digital control interface with easy-to-use features

• Fully compatible with Worcester Bosch smart controls and wireless thermostats

• Compact cupboard-fit size with simple replacing of older Worcester boilers

Suitable For

• 1–3 bedroom homes

• Up to 10–12 radiators

• One bathroom with standard hot water demand

Installation Note

To ensure correct performance and maintain the manufacturer warranty, the Worcester Greenstar 4000 25kW Combi Boiler must be installed and commissioned by a Gas Safe registered engineer.