Head to head
Telford Tempest 300 Indirect vs Viessmann Vitocal 150-A13
The Telford Tempest 300 Indirect is a indirect unvented hot water cylinder, 300 litres. The Viessmann Vitocal 150-A13 is a r290 air source heat pump, 8.1 kw heat output.
Last reviewed 13 September 2026
Specifications side by side
| Telford Tempest 300 Indirect | Viessmann Vitocal 150-A13 | |
|---|---|---|
| Dimensions | 1750 mm high x 580 mm diameter | 920 x 450 x 360 mm (H x W x D) (indoor unit); 841 x 1144 x 600 mm (H x W x D, single fan) (outdoor unit) |
| Weight | 61 kg | 162 kg (single fan) (outdoor unit) |
| Capacity | 300 litres | - |
| Material | 2304 duplex stainless steel | - |
| Relief valve setting | 7 bar / 90C | - |
| Immersion heater | 3kW, 240V single phase, included | - |
| Warranty | Lifetime guarantee on the body with annual service, 2 year component guarantee | - |
| Heat output | - | 8.1 kW at A7/W35 |
| COP | - | 4.7-5.0 at A7/W35 |
| Refrigerant | - | R290 (propane), GWP 0.02 |
| Sound power | - | 51 dB(A) assessed total at A7/W55 |
| Max flow temperature | - | 70C down to -10C outdoor |
Sources: Telford Tempest 300 Indirect, Viessmann Vitocal 150-A13. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the Tempest 300 Indirect if...
A 300 litre indirect cylinder for a larger household or a property with high simultaneous hot water demand, part of Telford's Tempest range. Like the smaller direct model it carries a lifetime body guarantee when serviced annually.
Full Tempest 300 Indirect specifications →Buy or hire the Vitocal 150-A13 if...
A Vitocal 150-A monobloc-style split heat pump using the natural refrigerant R290, rated at 8.1kW and reaching a 70C flow for boiler-replacement work. Viessmann-trained installers can extend the standard warranty on registration.
Full Vitocal 150-A13 specifications →Common questions
What is the difference between the Telford Tempest 300 Indirect and the Viessmann Vitocal 150-A13?
The Telford Tempest 300 Indirect is a indirect unvented hot water cylinder, 300 litres; the Viessmann Vitocal 150-A13 is a r290 air source heat pump, 8.1 kW heat output.
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