Head to head
Glow-worm Energy Combi 25C 25kW vs Worcester Bosch Greenstar 2000 30kW combi
The Worcester Bosch Greenstar 2000 30kW combi has 4kW more hot water output and runs 1.6 litres a minute more hot water.
Last reviewed 13 September 2026
Key differences
- Hot water output: the Worcester Bosch Greenstar 2000 30kW combi has 4kW more hot water output.
- Hot water flow rate: the Worcester Bosch Greenstar 2000 30kW combi runs 1.6 litres a minute more hot water.
Specifications side by side
| Glow-worm Energy Combi 25C 25kW | Worcester Bosch Greenstar 2000 30kW combi | |
|---|---|---|
| Hot water output | 25.7 kW | 30 kW |
| Central heating output | 18 kW | 3-24 kW |
| ErP class | A | A |
| Seasonal efficiency | 94% | 94% |
| Dimensions | 700 x 390 x 280 mm | 724 x 400 x 300 mm |
| Weight | 32 kg | 32.1 kg |
| Warranty | 7 years | 7 years when installed with Greenstar System Filter |
| Hot water flow rate | 10.4 litres per minute | 12 litres per minute at 35 C rise |
Sources: Glow-worm Energy Combi 25C 25kW, Worcester Bosch Greenstar 2000 30kW combi. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the Energy Combi 25C 25kW if...
A gas combi boiler with 25.7 kW of hot water output, sized for a flat or small house with one bathroom. It delivers about 10.4 litres per minute of hot water, which decides how well a shower runs while a tap is on. Warranty: 7 years. Seasonal efficiency is 94%.
Full Energy Combi 25C 25kW specifications →Buy or hire the Greenstar 2000 30kW combi if...
- you want one that has 4kW more hot water output
- you want one that runs 1.6 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 litres per minute at 35 C rise of hot water, which decides how well a shower runs while a tap is on. Warranty: 7 years when installed with Greenstar System Filter. Seasonal efficiency is 94%.
Full Greenstar 2000 30kW combi specifications →Common questions
What is the difference between the Glow-worm Energy Combi 25C 25kW and the Worcester Bosch Greenstar 2000 30kW combi?
The Worcester Bosch Greenstar 2000 30kW combi has 4kW more hot water output and runs 1.6 litres a minute more hot water. The Glow-worm Energy Combi 25C 25kW is a gas combi boiler, 25.7 kW hot water output; the Worcester Bosch Greenstar 2000 30kW combi is a gas combi boiler, 30 kW hot water output.
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