Gas
| Range | Standard guarantee | Greenstar System Filter | Extended |
|---|---|---|---|
| Greenstar 8000+ | 8 years | 10 years | 12 years |
| Greenstar 8000+ Style | 8 years | 10 years | 12 years |
| Greenstar 4000 | 7 years | 8 years | 10 years |
| Greenstar CDi Compact | 7 years | 8 years | 10 years |
| Greenstar i System Compact | 7 years | 8 years | 10 years |
| Greenstar 8000 F | 7 years | 8 years | 10 years |
| Greenstar Ri | 7 years | 8 years | 10 years |
| Greenstar Ri Compact | 7 years | 8 years | 10 years |
| Greenstar 2000 | 7 years | 7 years | Not offered |
| Greenstar 1000 | 5 years | 5 years | Not offered |
Oil
| Range | Standard guarantee | Greenstar System Filter | Extended |
|---|---|---|---|
| Greenstar Heatslave II | 2 years | 5 years | 7 years |
| Greenstar Danesmoor | 2 years | 5 years | 7 years |
The extended length is what a Worcester Bosch Accredited Installer or Accredited Partner can offer when the boiler is fitted with a Greenstar System Filter. In 2026, a loyalty-scheme installer who is not accredited can buy that same length for £40 through their loyalty account.
A Bosch System Filter Micro does not add years. On the 8000+ and 8000+ Style the guarantee stays at 8 years. On the 8000 F, Ri and Ri Compact it stays at 7 years.
The Greenstar 1000 and 2000 lengths already assume a system filter is fitted. It can be a Worcester Bosch filter or another brand, and those lengths cannot be extended.
Worcester changes the lengths. Confirm the current guarantee for the boiler you are fitting before you quote it. See also Worcester Bosch.