The best, reborn.

Created from the DNA of the UK’s best-selling Greenstar i

greenstar 4000

Introducing the Greenstar 4000

Built on all the tried, tested and much-loved features of the Greenstar i, the Greenstar 4000 is instantly familiar and yet totally transformed.

We’ve raised the bar with the speed and ease of installation, commissioning and servicing, alongside improvements in efficiency and control. We’ve even made the price the same as its predecessor.

The 4000 range is available in both natural gas and LPG for:

  • Combi - 25kW and 30kW with hot water flow rates up to 12.3 l/min.
  • System - 12 – 24kW

The 4000 will also carry the same guarantee lengths as its predecessor the Greenstar i. Please note the Greenstar i System 27 and 30kW variants with the WB7 compact heat exchanger will continue to be available.

10 year guarantee

Guarantee Lengths


Standard Guarantee  - 7 Years

With any Greenstar System Filter - 8 Years

With any Greenstar System Filter + £150 (Non-WAI Excelerate members only) - 10 Years

*Full terms and conditions apply


4000 training courses

Use our online booking system to secure a place on the free Greenstar 4000 webinar training course.

Can’t attend in person? Join our Facebook group ‘Worcester Bosch Training Academy’ where we’ll be releasing bite size training videos daily in June.

Sign up

Why Worcester Bosch


Sign up to Excelerate

Open to all installers, earn loyalty points when you install our Greenstar boilers and accessories!


10 year guarantee

Terms and conditions apply. Available to Excelerate members. Non-Worcester Accredited Installers, can achieve this guarantee length by fitting any Greenstar System Filter and a £150 payment.


Simple Switch

A real time-saver for seamless swapping out with iJunior, Si combi and i System (2005-2015).


Join our virtual and face to face events

We’ll be running a series of online events where we’ll reveal everything behind the case and more.  The events are available to all with a gas safe number.

When the time is right and it’s safe to do so, we’ll also be hosting face to face events up and down the country.