Head to head
Joule Cyclone Air 150L Direct vs NIBE S2125 Model 8
The Joule Cyclone Air 150L Direct is a direct unvented hot water cylinder, 150 litres. The NIBE S2125 Model 8 is a air/water heat pump, up to 5.4 kw heat output.
Last reviewed 13 September 2026
Specifications side by side
| Joule Cyclone Air 150L Direct | NIBE S2125 Model 8 | |
|---|---|---|
| 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 | - | 5.33 kW (average climate), 5.4 kW (cold climate) |
| SCOP | - | 5.0 at 35C, 3.7 at 55C (average climate); 4.1 at 35C, 3.2 at 55C (cold climate) |
| Sound power | - | 49 dB(A) at nominal rating (EN12102) |
| Weight | - | 150 kg |
| Max flow temperature | - | up to 75C |
Sources: Joule Cyclone Air 150L Direct, NIBE S2125 Model 8. 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 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 →Common questions
What is the difference between the Joule Cyclone Air 150L Direct and the NIBE S2125 Model 8?
The Joule Cyclone Air 150L Direct is a direct unvented hot water cylinder, 150 litres; the NIBE S2125 Model 8 is a air/water heat pump, up to 5.4 kW heat output.
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