Head to head
Glow-worm Energy Combi 25C 25kW vs Vaillant ecoTEC Pro 24kW combi
The Glow-worm Energy Combi 25C 25kW comes with 5 years more warranty and has 2kW more hot water output. The Vaillant ecoTEC Pro 24kW combi puts out 7kW more to the radiators.
Last reviewed 13 September 2026
Key differences
- Warranty: the Glow-worm Energy Combi 25C 25kW comes with 5 years more warranty.
- Central heating output: the Vaillant ecoTEC Pro 24kW combi puts out 7kW more to the radiators.
- Hot water output: the Glow-worm Energy Combi 25C 25kW has 2kW more hot water output.
- Hot water flow rate: the Glow-worm Energy Combi 25C 25kW runs 0.8 litres a minute more hot water.
- Seasonal efficiency: the Glow-worm Energy Combi 25C 25kW is 1 points more efficient.
Specifications side by side
| Glow-worm Energy Combi 25C 25kW | Vaillant ecoTEC Pro 24kW combi | |
|---|---|---|
| Hot water output | 25.7 kW | 23.4 kW |
| Central heating output | 18 kW | 24.8 kW |
| ErP class | A | A |
| Seasonal efficiency | 94% | 93% |
| Dimensions | 700 x 390 x 280 mm | 720 x 440 x 338 mm |
| Weight | 32 kg | 38 kg |
| Warranty | 7 years | 2 years standard, 7 years with Vaillant Advance registration |
| Hot water flow rate | 10.4 litres per minute | 9.6 litres per minute |
Sources: Glow-worm Energy Combi 25C 25kW, Vaillant ecoTEC Pro 24kW 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...
- you want one that comes with 5 years more warranty
- you want one that has 2kW more hot water output
- you want one that runs 0.8 litres a minute more hot water
- you want one that is 1 points more efficient
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 ecoTEC Pro 24kW combi if...
- you want one that puts out 7kW more to the radiators
A gas combi boiler with 23.4 kW of hot water output, sized for a flat or small house with one bathroom. It delivers about 9.6 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 24kW combi specifications →Common questions
What is the difference between the Glow-worm Energy Combi 25C 25kW and the Vaillant ecoTEC Pro 24kW combi?
The Glow-worm Energy Combi 25C 25kW comes with 5 years more warranty and has 2kW more hot water output. The Vaillant ecoTEC Pro 24kW combi puts out 7kW more to the radiators. The Glow-worm Energy Combi 25C 25kW is a gas combi boiler, 25.7 kW hot water output; the Vaillant ecoTEC Pro 24kW combi is a gas combi boiler, 23.4 kW hot water output.
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