Head to head
NIBE S2125 Model 12 vs Vaillant aroTHERM plus 7kW
The NIBE S2125 Model 12 is a air/water heat pump, up to 8.4 kw heat output. The Vaillant aroTHERM plus 7kW is a r290 monobloc air source heat pump, 7 kw heat output.
Last reviewed 13 September 2026
Specifications side by side
| NIBE S2125 Model 12 | Vaillant aroTHERM plus 7kW | |
|---|---|---|
| Heat output | 6.80-7.60 kW (average climate), 8.4 kW (cold climate) | 7 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 |
| Sound power | 49 dB(A) at nominal rating (EN12102) | 58 dB(A) at A7/W35, 60 dB(A) at A7/W55 |
| Dimensions | 1070 x 1130 x 820 mm (H x W x D) | 1565 x 1100 x 450 mm (H x W x D) |
| Weight | 160 kg | 194 kg (operating) |
| Max flow temperature | up to 75C | 75C |
| Refrigerant | - | R290 (propane), low GWP |
Sources: NIBE S2125 Model 12, Vaillant aroTHERM plus 7kW. 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 7kW if...
A mid-size aroTHERM plus for a typical three-bed house. It is taller and heavier than the 5kW unit, reflecting a larger outdoor cabinet, and shares the same R290 refrigerant and 75C maximum flow temperature.
Full aroTHERM plus 7kW specifications →Common questions
What is the difference between the NIBE S2125 Model 12 and the Vaillant aroTHERM plus 7kW?
The NIBE S2125 Model 12 is a air/water heat pump, up to 8.4 kW heat output; the Vaillant aroTHERM plus 7kW is a r290 monobloc air source heat pump, 7 kW heat output.
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