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Q:

What's the Warmest Sleeping Bag?

I'm looking for a sleeping bag for extreme cold temperatures. I'm talking Arctic. What's my best option?

nemo canon 40 sleeping bag

Fighting the cold: Polar explorer Robert Peary and the modern Nemo Canon -40.     Photo: Courtesy of Nemo

A:In February, Nemo launched an odd-looking sleeping bag called the Canon -40, made for surviving the world’s coldest temperatures. The whole package looks like it was air-dropped from outer space. At the head end, the “Stove Pipe Tunnel Hood” looks like a periscope or snorkel sticking out of the fabric. Along the sides, the “Thermo Gills” look like, well, fish gills.

Nemo, a 19-person gear manufacturer from New Hampshire, has been on a roll lately with their designs for innovative camping equipment. First, there was a tent held up by pressurized tubes instead of aluminum poles. Then there was a uniquely-shaped sleeping bag, the “Spoon Series”, which hugs the human body better than traditional bags. Now, the Canon -40 sleeping bag is winning awards from reviewers at sites and magazines around the world.

The day we talked with design director Suzanne Turell about the process of making the Canon, her office was busy with prototypes for tent pole clips coming off the 3-D printer, and meetings with the design and engineering team working on plans for products three years out.

Turell, a 33-year-old surfer and hiker, first became interested in outdoor gear as a kid while camping with her dad. Her love of the outdoors solidified while hiking the length of the Appalachian Trail, a trip that finished up just days before she entered grad school at the Rhode Island School of Design. “Every day, for five months, all I was thinking about was what I would do better with each piece of gear,” Turell says. “I thought of how I would make my shoes better. Every time I set up my tent I thought how I would make it easier to use. Then, as soon as I got off the trail, I started school.”

When she and the other designers sat down to make a sleeping bag for very cold temps, they looked at the jackets of polar explorers, which often have an extended head covering. “The hoods are made to roll forward, so that you get this long opening in front of your face that you can close,” explains Turell. “The idea is to warm the air that you’re breathing. Otherwise, your lungs aren’t ready for the big jump between temperatures.”

The designers realized they were on to something when they saw the documentary Cold at the Banff Mountain Film Festival. “The film showed people sleeping in negative-70 air or something ridiculous, and they were choking on the air while they were sleeping, says Turell. "It was painfully obvious that you need something more than the gear currently offered.”

Soon after creating the prototype for the Canon, one tester reported a flaw that the design team couldn't ignore. "He said the bag was warm,” recalls Turell. “But in some ways it was too warm because when it wasn’t negative-40 degrees, he couldn’t vent it properly."

The designers, who are all avid campers, knew the phenomenon all too well. “It may be zero degrees or negative 20, but you’re in a bag for the extreme cold and get really sweaty. Your sleep gets interrupted,” she says. “We’d all experienced this in the company, and so it was a light-bulb moment. We all started thinking about ways to compromise the baffles [the columns of insulation sewn into the fabric] so that they would let out the warmth in a controlled way." The designers’ solution was to place a zipper that spreads the baffles apart but doesn’t let air flow through the wind-cutting fabric.

According to Turell, the next step in Nemo's evolution as a company might not come from the outdoors industry at all. "It might be something we see in the residential building industry, and you think, ‘A tent is not that different from a house. I wonder what would happen if you used that on a tent? How can make it weigh only an ounce?’" she says. "We’re always trying to find innovations that could apply to what we’re doing.”

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