Head to head
NIBE S2125 Model 8 vs Worcester Bosch Greenstar 5800i AW 7kW
The NIBE S2125 Model 8 is a air/water heat pump, up to 5.4 kw heat output. The Worcester Bosch Greenstar 5800i AW 7kW is a r290 monobloc air source heat pump, 7.97 kw heat output.
Last reviewed 13 September 2026
Specifications side by side
| NIBE S2125 Model 8 | Worcester Bosch Greenstar 5800i AW 7kW | |
|---|---|---|
| Heat output | 5.33 kW (average climate), 5.4 kW (cold climate) | 7.97 kW at 7/35C |
| SCOP | 5.0 at 35C, 3.7 at 55C (average climate); 4.1 at 35C, 3.2 at 55C (cold climate) | 4.54 (MCS, 35C flow) |
| Dimensions | 1070 x 1130 x 820 mm (H x W x D) | 800 x 1100 x 540 mm (H x W x D) |
| Weight | 150 kg | 143 kg |
| Max flow temperature | up to 75C | 75C |
| Sound power | 49 dB(A) at nominal rating (EN12102) | - |
| Refrigerant | - | R290 (propane) |
| Sound pressure | - | 42 dB(A) |
Sources: NIBE S2125 Model 8, Worcester Bosch Greenstar 5800i AW 7kW. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the S2125 Model 8 if...
A smaller NIBE S2125 rated to keep working in cold climates, reaching up to 65C flow even at -25C outdoors. It suits a smaller house where cold-weather reliability matters more than raw output.
Full S2125 Model 8 specifications →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 →Common questions
What is the difference between the NIBE S2125 Model 8 and the Worcester Bosch Greenstar 5800i AW 7kW?
The NIBE S2125 Model 8 is a air/water heat pump, up to 5.4 kW heat output; the Worcester Bosch Greenstar 5800i AW 7kW is a r290 monobloc air source heat pump, 7.97 kW heat output.
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