Head to head
NIBE S2125 Model 12 vs Vaillant aroTHERM plus 10kW
The NIBE S2125 Model 12 is a air/water heat pump, up to 8.4 kw heat output. The Vaillant aroTHERM plus 10kW is a r290 monobloc air source heat pump, 10 kw heat output.
Last reviewed 13 September 2026
Specifications side by side
| NIBE S2125 Model 12 | Vaillant aroTHERM plus 10kW | |
|---|---|---|
| Heat output | 6.80-7.60 kW (average climate), 8.4 kW (cold climate) | 10 kW |
| SCOP | 5.0 at 35C, 3.8 at 55C (average climate); 4.2 at 35C, 3.4 at 55C (cold climate) | up to 5.03 |
| Max flow temperature | up to 75C | 75C |
| Sound power | 49 dB(A) at nominal rating (EN12102) | - |
| Dimensions | 1070 x 1130 x 820 mm (H x W x D) | - |
| Weight | 160 kg | - |
| Refrigerant | - | R290 (propane), low GWP |
Sources: NIBE S2125 Model 12, Vaillant aroTHERM plus 10kW. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the S2125 Model 12 if...
The larger NIBE S2125, sized for a medium house and rated to hold output down to -25C outdoor temperature. It shares its cabinet size with the smaller model but weighs 10 kg more for the larger compressor.
Full S2125 Model 12 specifications →Buy or hire the aroTHERM plus 10kW if...
The larger aroTHERM plus, sized for a bigger house with a higher heat loss. It keeps the same R290 refrigerant and 75C maximum flow temperature as the smaller units in the range, so it can usually work with existing radiators.
Full aroTHERM plus 10kW specifications →Common questions
What is the difference between the NIBE S2125 Model 12 and the Vaillant aroTHERM plus 10kW?
The NIBE S2125 Model 12 is a air/water heat pump, up to 8.4 kW heat output; the Vaillant aroTHERM plus 10kW is a r290 monobloc air source heat pump, 10 kW heat output.
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