Worcester Bosch Greenstar 4000 21kW System Boiler

Worcester Bosch Greenstar 4000 21kW System Boiler

SKU: BC-386



This product is not sold by WarmZilla
The new Greenstar 4000 range is Worcester Bosch’s latest edition to the family and will be replacing the Greenstar i range.

With an efficiency rating of 94% and an ErP A-rating for both central heating and hot water, this system boiler could potentially help you to reduce your energy bills.

The Greenstar 4000 system boiler range is available in 5 outputs options of 12kW, 15kW, 18kW, 21kW and 24kW. This boiler model has a central heating output of 21kW, great for homes with up to 15 radiators and a bathroom.

When purchasing a new or replacement system boiler, you will need to take into consideration, space in your home for an additional hot water storage tank. These are typically installed in an airing cupboard or similar size space in your home.

This is because system boilers are fed with cold water from the mains, similarly to a combi boiler, however, a system boiler stores the heated water in a hot water tank for later use. For this reason, system boilers are not recommended for homes with limited space. On the plus side, the Greenstar 4000 range is also available as a combi boiler.

Worcester Bosch offers a Simple Switch option to replace your old i Junior or Si combi or system boiler. Simple Switch refers to sharing the same positions for the top and bottom wall-frame screws, meaning that replacing your old Greenstar i or Si boiler, should be simple and straightforward.

The Worcester Bosch Greenstar 4000 is compatible with a range of controls to enhance your experience at home. These include the Comfort+, the Comfort+ I RF and II RF and the EasyBosch controls. 

kW Output
21 KW
ERP Rating
A Rated
Energy Efficiency
94 %
Which Review Score
Brochure URL
Height 720mm
Width 400mm
Depth 310mm