Head to head
Vaillant ecoTEC Pro 30kW combi vs Worcester Bosch Greenstar 4000 25kW combi
The Worcester Bosch Greenstar 4000 25kW combi comes with 8 years more warranty. The Vaillant ecoTEC Pro 30kW combi has 5kW more hot water output and runs 1.8 litres a minute more hot water.
Last reviewed 13 September 2026
Key differences
- Warranty: the Worcester Bosch Greenstar 4000 25kW combi comes with 8 years more warranty.
- Hot water output: the Vaillant ecoTEC Pro 30kW combi has 5kW more hot water output.
- Hot water flow rate: the Vaillant ecoTEC Pro 30kW combi runs 1.8 litres a minute more hot water.
- Central heating output: the Vaillant ecoTEC Pro 30kW combi puts out 1kW more to the radiators.
- Seasonal efficiency: the Worcester Bosch Greenstar 4000 25kW combi is 1 points more efficient.
Specifications side by side
| Vaillant ecoTEC Pro 30kW combi | Worcester Bosch Greenstar 4000 25kW combi | |
|---|---|---|
| Hot water output | 30 kW | 25 kW |
| Central heating output | 25.7 kW | 25 kW |
| ErP class | A | A |
| Seasonal efficiency | 93% | 94% |
| Dimensions | 720 x 440 x 335 mm | 710 x 400 x 310 mm |
| Weight | 39 kg | 32.0 kg |
| Warranty | 2 years standard, 7 years with Vaillant Advance registration | 10 years |
| Hot water flow rate | 12.3 litres per minute | 10.5 litres per minute |
Sources: Vaillant ecoTEC Pro 30kW combi, Worcester Bosch Greenstar 4000 25kW combi. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the ecoTEC Pro 30kW combi if...
- you want one that has 5kW more hot water output
- you want one that runs 1.8 litres a minute more hot water
- you want one that puts out 1kW more to the radiators
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: 2 years standard, 7 years with Vaillant Advance registration. Seasonal efficiency is 93%.
Full ecoTEC Pro 30kW combi specifications →Buy or hire the Greenstar 4000 25kW combi if...
- you want one that comes with 8 years more warranty
- you want one that is 1 points more efficient
A gas combi boiler with 25 kW of hot water output, sized for a flat or small house with one bathroom. It delivers about 10.5 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 25kW combi specifications →Common questions
What is the difference between the Vaillant ecoTEC Pro 30kW combi and the Worcester Bosch Greenstar 4000 25kW combi?
The Worcester Bosch Greenstar 4000 25kW combi comes with 8 years more warranty. The Vaillant ecoTEC Pro 30kW combi has 5kW more hot water output and runs 1.8 litres a minute more hot water. The Vaillant ecoTEC Pro 30kW combi is a gas combi boiler, 30 kW hot water output; the Worcester Bosch Greenstar 4000 25kW combi is a gas combi boiler, 25 kW hot water output.
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