Head to head
Joule Cyclone Air 150L Direct vs NIBE S2125 Model 12
The Joule Cyclone Air 150L Direct is a direct unvented hot water cylinder, 150 litres. The NIBE S2125 Model 12 is a air/water heat pump, up to 8.4 kw heat output.
Last reviewed 13 September 2026
Specifications side by side
| Joule Cyclone Air 150L Direct | NIBE S2125 Model 12 | |
|---|---|---|
| Dimensions | 1196 x 540 x 540 mm (H x W x D) | 1070 x 1130 x 820 mm (H x W x D) |
| Capacity | 150 litres | - |
| Heat-up time | 57 minutes (full tank, 6kW immersion) | - |
| Immersion heater | 6kW (2 x 3kW) | - |
| Warranty | 1 year manufacturer's warranty | - |
| Heat output | - | 6.80-7.60 kW (average climate), 8.4 kW (cold climate) |
| SCOP | - | 5.0 at 35C, 3.8 at 55C (average climate); 4.2 at 35C, 3.4 at 55C (cold climate) |
| Sound power | - | 49 dB(A) at nominal rating (EN12102) |
| Weight | - | 160 kg |
| Max flow temperature | - | up to 75C |
Sources: Joule Cyclone Air 150L Direct, NIBE S2125 Model 12. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the Cyclone Air 150L Direct if...
A 150 litre direct unvented cylinder from Joule's Cyclone range, heated by twin immersion elements rather than a boiler or heat pump coil. It suits a property with electric-only heating or a holiday let, reheating a full tank in around 57 minutes.
Full Cyclone Air 150L Direct specifications →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 →Common questions
What is the difference between the Joule Cyclone Air 150L Direct and the NIBE S2125 Model 12?
The Joule Cyclone Air 150L Direct is a direct unvented hot water cylinder, 150 litres; the NIBE S2125 Model 12 is a air/water heat pump, up to 8.4 kW heat output.
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