Worcester Bosch Greenstar 4000 28kW
The Greenstar 4000 is Worcester Bosch's entry-level condensing combi boiler and one of the UK's best-selling models. It delivers reliable performance, 94% efficiency, and comes with an up to 12-year warranty when fitted by an accredited installer like Corby Boiler Installations.
Technical Specifications
Key Features
- 94% ErP seasonal efficiency
- 28 kW heat output
- Built-in frost protection
- Easy-clean condensate trap
- OpenTherm compatibility for smart thermostats
- Pre-plumbing jig available for new installs
Best For
2–3 bed homes with one bathroom and moderate hot water demand.
Supply & installation
Fully installed, inc. flue, filter & VAT — get a personalised quote online.
Get Your QuoteCommon Questions About the Greenstar 4000 28kW
Is the Greenstar 4000 reliable?
Yes — it's one of the UK's most tested combi boilers. Independent surveys put Worcester Bosch at the top of reliability rankings year after year.
What warranty does the Greenstar 4000 come with?
Standard 5-year warranty, extending to 10 or 12 years when installed by a Worcester Bosch Accredited Installer.
Does the Greenstar 4000 work with a smart thermostat?
Yes — it has OpenTherm compatibility and works with Nest, Hive, Tado, and the Worcester Bosch Wave thermostat.
Other Worcester Bosch Models We Install
Compare With Other Combi Boilers
Ready to Get the Greenstar 4000 28kW Installed?
We supply and install the Worcester Bosch Greenstar 4000 28kW across Corby, Kettering, Northampton, and all surrounding areas.