Head to head
Vaillant ecoTEC plus 825 25kW combi vs Worcester Bosch Greenstar 4000 25kW combi
The Worcester Bosch Greenstar 4000 25kW combi puts out 4kW more to the radiators. The Vaillant ecoTEC plus 825 25kW combi has 0kW more hot water output.
Last reviewed 13 September 2026
Key differences
- Central heating output: the Worcester Bosch Greenstar 4000 25kW combi puts out 4kW more to the radiators.
- Hot water output: the Vaillant ecoTEC plus 825 25kW combi has 0kW more hot water output.
Specifications side by side
| Vaillant ecoTEC plus 825 25kW combi | Worcester Bosch Greenstar 4000 25kW combi | |
|---|---|---|
| Hot water output | 25.4 kW | 25 kW |
| Central heating output | 20.8 kW | 25 kW |
| ErP class | A | A |
| Seasonal efficiency | 94% | 94% |
| Dimensions | 720 x 440 x 338 mm | 710 x 400 x 310 mm |
| Weight | 36 kg | 32.0 kg |
| Warranty | 10 years with Vaillant Advance Boiler Protection Kit | 10 years |
| Hot water flow rate | 10.5 litres per minute | 10.5 litres per minute |
Sources: Vaillant ecoTEC plus 825 25kW 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 plus 825 25kW combi if...
- you want one that has 0kW more hot water output
A gas combi boiler with 25.4 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 with Vaillant Advance Boiler Protection Kit. Seasonal efficiency is 94%.
Full ecoTEC plus 825 25kW combi specifications →Buy or hire the Greenstar 4000 25kW combi if...
- you want one that puts out 4kW more to the radiators
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 plus 825 25kW combi and the Worcester Bosch Greenstar 4000 25kW combi?
The Worcester Bosch Greenstar 4000 25kW combi puts out 4kW more to the radiators. The Vaillant ecoTEC plus 825 25kW combi has 0kW more hot water output. The Vaillant ecoTEC plus 825 25kW combi is a gas combi boiler, 25.4 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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