Worcester Bosch Greenstar 4000
Highly reliable A-rated combi boiler with up to 10-year parts and labour warranty
The Worcester Bosch Greenstar 4000 is the benchmark for reliability in UK gas boilers. Available in 25 kW and 30 kW outputs, it achieves 94% efficiency (ErP A-rated) with NOx emissions of just 40 mg/kWh. The headline feature is its 10-year parts and labour warranty — the industry's strongest — backed by Worcester Bosch's renowned service network. Compatible with all major smart thermostats, it is the boiler of choice for homeowners who want reliability above all else.
Worcester Bosch Greenstar 4000 — supplied and installed by CCS Heating & Renewables
Technical Specifications
Key Benefits
10-Year Parts & Labour Warranty
The strongest warranty in the market — covers both parts and the cost of labour for a full decade, providing genuine peace of mind.
94% A-Rated Efficiency
ErP A-rated efficiency means lower gas bills and reduced carbon emissions versus older G or F-rated boilers.
Smart Control Compatible
Works with all major smart thermostats including Hive, Nest, and tado° — as well as Worcester Bosch's own intelligent controls.
Compact Footprint
Slim profile at just 310 mm deep — fits neatly in a standard kitchen cupboard or utility space.
Low NOx Emissions
40 mg/kWh NOx rating — among the cleanest gas boilers available, meeting the strictest UK air quality standards.
Reliable Brand
Worcester Bosch is consistently ranked the most trusted boiler brand in the UK by independent consumer surveys.
Ideal For
- Homes replacing an old or inefficient gas boiler
- Properties not yet suitable for a heat pump (e.g., due to insulation levels)
- Homeowners wanting the longest warranty and most reliable brand
- Gas-connected homes wanting smart heating control
Installation Service
Gas Safe registered boiler installation, replacement, and servicing. We fit Worcester Bosch, Vaillant, and Viessmann boi...
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