Greenstar i System (9kW to 24kW) overview
Our Greenstar i System boiler is our most popular system boiler that is suitable for small to medium sized homes.
This boiler can also be used with our high efficiency Greenstore cylinders for a complete Worcester system solution for your home.
- Simple boiler controls with clear information display
- Suitable for homes where the heating system includes a hot water storage cylinder
- Choice of controls enables greater comfort and economy*
- Can be used with Greenskies solar panels for energy and cost savings
- Low energy pump reduces electrical usage
- Large Condensesure style siphon built into the boiler - eliminates frost risk †




This efficiency rating icon is for a product within a range of products. View all products in this range
Technical Details
Greenstar 9i System | Greenstar 12i System | Greenstar 15i System | Greenstar 18i System | Greenstar 21i System | Greenstar 24i System | |
---|---|---|---|---|---|---|
ErP Efficiency Rating |
A
|
A
|
A
|
A
|
A
|
A
|
ErP Data Sheet | ErP Data Sheet | ErP Data Sheet | ErP Data Sheet | ErP Data Sheet | ErP Data Sheet | ErP Data Sheet |
LPG model available | ||||||
EasyControl Compatible | ||||||
Solar Compatible | ||||||
Control Options | ||||||
Central heating output (kW) | 9 | 12 | 15 | 18 | 21 | 24 |
Dimensions (mm) height x width x depth | 710 x 400 x 330 | 710 x 400 x 330 | 710 x 400 x 330 | 710 x 400 x 330 | 710 x 400 x 330 | 710 x 400 x 330 |
*With installation of optional built-in diverter valve
† The Condensesure Siphon has been proven to be effective at preventing frozen condensate at -15°C for a sustained period of 48 hours. 32mm pipework must be used and should not exceed 3 metreRelated documents
- Greenstar 12-24 i System ErP Operating Instructions Manufactured after 01.03.15
- Gas Consumer Brochure Manufactured after 01.01.16
Have you considered...
Find a local installer
Each heating system needs custom designing. Find and contact a Worcester Accredited Installer in your area to book a home visit and get a free quote.
Find the right boiler for you
Our Find a New Boiler tool is the easiest way to find and compare Worcester products which are suitable for your home and heating requirements and only takes a few minutes.
Find the right boiler for you