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Mountain Hardwear Phantom 0/-18 sleeping bag review: a winner for winter

The Mountain Hardwear Phantom 0/-18 sleeping bag is a seriously warm four-season bag that can only be bested by specialist brands producing kit for polar expeditions and high-altitude mountaineers

Mountain Hardwear Phantom 0/-18
(Image: © Mountain Hardwear)

Our Verdict

Premium materials, a tapered fit and box-wall construction makes this bag highly thermally efficient – a winner for winter camping.


  • Exceptionally warm
  • Lightweight


  • Expensive
  • Tapered fit
  • Down fill not hydrophobic

First impressions

Mountain Hardwear Phantom 0/-18 is the flagship sleeping bag in the Mountain Hardwear line. As it's name suggests, the Phantom 0 offers warmth down to a bone-chilling -18°C. Yet, given its four-season capabilities, it is lightweight and compact, with an impressively small pack size that ranks among the best in this class. It is filled with a hefty 850g/1lb 14oz of 850 fill power down, housed in either a Pertex Quantum or Gore-Tex Windstopper fabric shell.

The fit is highly tapered to maximise thermal efficiency. As such some might find it a little restrictive, though at high altitudes or low temperatures you’ll appreciate the extra warmth.

The one rather surprising omission is that the down fill has no hydrophobic treatment, though arguably the highly water-resistant outer renders this unnecessary.


RRP: $760 (US)/£570 (UK)
Weight: 1kg 208g/2lb 10.6 oz
Length: 218cm/86in (regular), 234cm/92in (long)
Max user height: 205cm/6ft 5in (regular), 220cm/7ft+ (large)
Pack size: 21x42cm/8.25x16.5in
Fill: 850-fill goose down
Comfort limit: -7°C/19.4°F
Limit: -18°C/0.4°F
Compatibility: 4-season

In the field

In full winter conditions, being zipped up in this bag as your breath condenses in the chill air of your tent is a wonderful sensation. It does a great job of locking in vital warmth thanks to a well-designed neck baffle and vertical box-wall chest baffles to counter down migration, which could otherwise cause cold spots.

The footbox and panelled hood are similarly well-constructed. To be honest, there’s little to fault. So if you’re a serious winter camper, you might consider this tried-and-tested four-season down bag for your next adventure.

Similarly, if you’re heading off on a trekking or mountaineering expedition at higher altitudes, it’s a good choice to take with you. Otherwise, in all honesty there’s a good chance that a bag delivering this much warmth will be overkill.