Head to head
Worcester Bosch Greenstar 5800i AW 7kW vs Worcester Bosch Greenstar 4000 25kW combi
The Worcester Bosch Greenstar 5800i AW 7kW is a r290 monobloc air source heat pump, 7.97 kw heat output. The Worcester Bosch Greenstar 4000 25kW combi is a gas combi boiler, 25 kw hot water output.
Last reviewed 13 September 2026
Specifications side by side
| Worcester Bosch Greenstar 5800i AW 7kW | Worcester Bosch Greenstar 4000 25kW combi | |
|---|---|---|
| Dimensions | 800 x 1100 x 540 mm (H x W x D) | 710 x 400 x 310 mm |
| Weight | 143 kg | 32.0 kg |
| Heat output | 7.97 kW at 7/35C | - |
| SCOP | 4.54 (MCS, 35C flow) | - |
| Refrigerant | R290 (propane) | - |
| Sound pressure | 42 dB(A) | - |
| Max flow temperature | 75C | - |
| Hot water output | - | 25 kW |
| Central heating output | - | 25 kW |
| ErP class | - | A |
| Seasonal efficiency | - | 94% |
| Warranty | - | 10 years |
| Hot water flow rate | - | 10.5 litres per minute |
Sources: Worcester Bosch Greenstar 5800i AW 7kW, 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 Greenstar 5800i AW 7kW if...
The larger 5800i AW unit, for a slightly bigger house than the 5kW model while sharing the same cabinet size and 42 dB(A) sound rating. Its R290 refrigerant and 75C flow temperature suit a radiator-based retrofit.
Full Greenstar 5800i AW 7kW specifications →Buy or hire the Greenstar 4000 25kW combi if...
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 Worcester Bosch Greenstar 5800i AW 7kW and the Worcester Bosch Greenstar 4000 25kW combi?
The Worcester Bosch Greenstar 5800i AW 7kW is a r290 monobloc air source heat pump, 7.97 kW heat output; the Worcester Bosch Greenstar 4000 25kW combi is a gas combi boiler, 25 kW hot water output.
GetBrent is an independent directory and is not a dealer for, nor affiliated with, either manufacturer. Model and brand names are the trademarks of their owners.