Head to head
Baxi 800 Combi 2 30kW vs Worcester Bosch Greenstar 4000 30kW combi
The Worcester Bosch Greenstar 4000 30kW combi puts out 9kW more to the radiators and is 1 points more efficient.
Last reviewed 13 September 2026
Key differences
- Central heating output: the Worcester Bosch Greenstar 4000 30kW combi puts out 9kW more to the radiators.
- Seasonal efficiency: the Worcester Bosch Greenstar 4000 30kW combi is 1 points more efficient.
- Hot water flow rate: the Worcester Bosch Greenstar 4000 30kW combi runs 0.1 litres a minute more hot water.
Specifications side by side
| Baxi 800 Combi 2 30kW | Worcester Bosch Greenstar 4000 30kW combi | |
|---|---|---|
| Hot water output | 30 kW | 30 kW |
| Central heating output | 21.2 kW | 30 kW |
| ErP class | A | A |
| Seasonal efficiency | 93% | 94% |
| Dimensions | 700 x 390 x 285 mm | 710 x 400 x 310 mm |
| Warranty | 10 years | 10 years |
| Hot water flow rate | 12.2 litres per minute | 12.3 litres per minute |
| Weight | - | 32.3 kg |
Sources: Baxi 800 Combi 2 30kW, Worcester Bosch Greenstar 4000 30kW combi. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the 800 Combi 2 30kW if...
A gas combi boiler with 30 kW of hot water output, sized for a three-bed house with one or two bathrooms. It delivers about 12.2 litres per minute of hot water, which decides how well a shower runs while a tap is on. Warranty: 10 years. Seasonal efficiency is 93%.
Full 800 Combi 2 30kW specifications →Buy or hire the Greenstar 4000 30kW combi if...
- you want one that puts out 9kW more to the radiators
- you want one that is 1 points more efficient
- you want one that runs 0.1 litres a minute more hot water
A gas combi boiler with 30 kW of hot water output, sized for a three-bed house with one or two bathrooms. It delivers about 12.3 litres per minute of hot water, which decides how well a shower runs while a tap is on. Warranty: 10 years. Seasonal efficiency is 94%.
Full Greenstar 4000 30kW combi specifications →Common questions
What is the difference between the Baxi 800 Combi 2 30kW and the Worcester Bosch Greenstar 4000 30kW combi?
The Worcester Bosch Greenstar 4000 30kW combi puts out 9kW more to the radiators and is 1 points more efficient. The Baxi 800 Combi 2 30kW is a gas combi boiler, 30 kW hot water output; the Worcester Bosch Greenstar 4000 30kW combi is a gas combi boiler, 30 kW hot water output.
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