Glossary · Boilers and boiler types
What is a Worcester Bosch boiler?
A Worcester Bosch boiler is a gas or oil boiler made by Worcester, Bosch Group, a UK company founded in Worcester in 1962 and part of the Bosch Group. Its main domestic gas range is called Greenstar. Guarantees of up to 12 years apply when an accredited installer fits the boiler with a Greenstar system filter.
Key points
- Worcester was founded in 1962 and its UK headquarters in Worcester also makes its gas boilers. Its oil boilers are made at Clay Cross in Derbyshire.
- Its combi ranges include Greenstar 1000, 4000 and 8000+. The company says combis come with up to a 12 year guarantee.
- The 12 year guarantee is for the Greenstar 8000+, fitted by a Worcester Accredited Installer with a Greenstar system filter.
- BASI is an accredited installer for Worcester Bosch and Vaillant and says accreditation is what unlocks the longer manufacturer warranty.
- Whatever the brand, a gas boiler must be installed and serviced by a Gas Safe registered engineer.
What a Worcester Bosch boiler is
Worcester, Bosch Group is a UK boiler manufacturer. Its own history page says it was formed in 1962 in Worcester and grew from a small engineering works into a market leader in boilers in the UK.[2]Worcester, Bosch Group, Company history The company says it became part of the Bosch Group in the 1990s. Its history timeline gives 1992 and its about page gives 1996, so treat the exact year as unsettled.[1]Worcester, Bosch Group, About Worcester Bosch[2]Worcester, Bosch Group, Company history
The product range covers gas and oil boilers, heat pumps, solar water heating, controls and accessories.[1]Worcester, Bosch Group, About Worcester Bosch Worcester says its UK headquarters in Worcester includes the manufacturing of gas boilers, and that a further site at Clay Cross in Derbyshire makes its oil boilers.[1]Worcester, Bosch Group, About Worcester Bosch The timeline also lists the arrival of the combi boiler in the UK in 1971 within the company’s history.[2]Worcester, Bosch Group, Company history
The Greenstar range
Greenstar is the name of Worcester’s domestic gas boiler family. For combi boilers, the company’s own page lists three ranges and describes each: the Greenstar 1000 for smaller homes that want to keep an eye on bills, efficiency and space, the Greenstar 4000 for medium-sized homes, and the Greenstar 8000+ with a modern design.[3]Worcester, Bosch Group, Combi boilers How a combi boiler works explains what a combi does, and BASI’s combi boilers page covers sizing.
| Range (combi) | Worcester’s description | Guarantee wording |
|---|---|---|
| Greenstar 1000 | Smaller homes that want to keep an eye on bills, efficiency and space | Not stated on the page |
| Greenstar 4000 | Medium-sized homes | Not stated on the page |
| Greenstar 8000+ | Modern design, newer features | Up to 12 years |
Worcester says its combi boilers come with up to a 12 year guarantee, and that the Greenstar 8000+ gets 12 years for customers who use a local Worcester Bosch Accredited Installer and a Worcester Bosch Greenstar system filter.[3]Worcester, Bosch Group, Combi boilers The detail varies by model, so check the guarantee for the exact boiler on your quote. The magnetic system filter page explains what the filter does.
Buying one through BASI
BASI says it is an accredited installer for both Worcester Bosch and Vaillant, and that accreditation is what unlocks the 10-year manufacturer warranty most fitters cannot offer.[4]BASI Heating, Worcester Bosch and Vaillant: side-by-side Its own comparison page lists a Greenstar 30 combi as a fixed-price package with a magnetic system filter and cleanse, and a 5-year manufacturer warranty.[4]BASI Heating, Worcester Bosch and Vaillant: side-by-side Prices and terms change, so look at boiler installation and the prices page for the current position. You can read the brand comparison with Vaillant on the manufacturers page, and the Vaillant boiler and Ideal boiler pages cover the other two brands BASI fits.
Safety and servicing
Any gas boiler, from any maker, must be fitted and worked on by a Gas Safe registered engineer. The HSE says anyone employed to work on gas appliances in domestic premises must be Gas Safe registered and competent in that area of gas work, and strongly advises that appliances, flues and pipework are serviced at least annually.[5]Health and Safety Executive, Domestic gas: frequently asked questions See the Gas Safe Register page for how to check an engineer.
Example
Neil in Baildon is replacing a 15-year-old boiler in a three-bedroom house. His installer proposes a Greenstar combi and explains that the longer guarantee depends on a Worcester Accredited Installer fitting it with a Greenstar system filter. Neil asks for the guarantee length for that exact model in writing, because the 12 year figure applies to the 8000+ and other models differ.
What people get wrong
Brand names suggest a single product. Worcester Bosch is a range of boilers, each with its own output, features and guarantee. A longer guarantee on one model does not carry over to another, and it depends on who fits it.
The other mistake is treating a brand as the whole decision. The right boiler depends on the size of the home, the hot water demand and the installer. The brand comes after those.
The bottom line
A Worcester Bosch boiler is a UK-made gas boiler from a company founded in Worcester in 1962, sold mainly as the Greenstar range. Its longest guarantee, up to 12 years, needs an accredited installer and a system filter. Choose the model by the size of your home and your hot water use, and have it fitted and serviced by a Gas Safe registered engineer.
Common questions
Where are Worcester Bosch boilers made?
Worcester says its UK headquarters in Worcester includes the manufacturing of gas boilers, and that its oil boilers are made at a second site in Clay Cross, Derbyshire.
How long is the guarantee on a Worcester Bosch boiler?
Worcester says combis come with up to 12 years. The 12 year term is for the Greenstar 8000+ when a Worcester Accredited Installer fits it with a Greenstar system filter. Other models have shorter terms.
What is the Greenstar range?
Greenstar is Worcester's family of gas boilers. For combis the company lists the Greenstar 1000 for smaller homes, the 4000 for medium-sized homes and the 8000+ at the top of the range.
Do I need a special installer for the longer guarantee?
Yes. Worcester ties its 12 year guarantee to a Worcester Accredited Installer. BASI says it is accredited for Worcester Bosch and Vaillant and offers up to a 10-year warranty on fitted boilers.
Sources
We cite the original source for every figure: government, regulators, standards bodies and manufacturers' own documents. Each one shows the date we last checked it.
- Worcester, Bosch Group. About Worcester Bosch. Checked 11 November 2026. ↩
- Worcester, Bosch Group. Company history. Checked 11 November 2026. ↩
- Worcester, Bosch Group. Combi boilers. Checked 11 November 2026. ↩
- BASI Heating. Worcester Bosch and Vaillant: side-by-side. Checked 11 November 2026. ↩
- Health and Safety Executive. Domestic gas: frequently asked questions. Checked 11 November 2026. ↩