Sleeping Bag Review: Nemo ‘Thermal Gills’ Vent Heat

A built-for-women sleeping bag has innovations to increase comfort, breathability, and water resistance.

Nemo modifies the mummy design of traditional sleeping bags with its Rave 15. In a category that suffers from sameness, the tradition ends here.

I tested the 15-degree down Rave 15 sleeping bag over the last few months in tents and the open air, and in temps ranging from 15 to 40 degrees F.

From its design to the materials used, I found it fit for a wide range. Read my full review below.

Nemo Rave 15: Thermo Gills

The key to this bag are its “Thermo Gills” — two zippered slits within arm’s reach on the front of the bag. You can open them to let heat out, but they don’t let cold air (drafts) in too much.

The company first incorporated this feature into its Canon -40 to allow the bag to be used in bitter cold or milder temps. Check out the FLIR images taken from a thermal-imaging camera below. You can see the areas of heat loss and the extent of that loss.

Built-in Blanket

As nice as the gills are for temp regulation, the feature I love most on the Rave 15 is its “blanket fold.”

This is a puffy extra section of material that you can either tuck in around your neck for added warmth (like a draft collar) or push out for extra ventilation.

It serves another surprise purpose: No bag I’ve ever used has successfully covered the zipper pull. Roll over at night, and there it is, an annoying piece of metal poking your eye. The Rave 15’s blanket fold ensures you never have to feel the cold, hard zipper-pull again.

Sleeping Bag Features

Vertical baffling keeps the down fill from migrating, helping prevent cold spots. An integrated pillow pocket with a down jacket makes for nice neck and head support.

A phone-size pocket by the right shoulder was used to store keys and lip balm. Because of its placement (and because the entire bag did not turn when I did) I never noticed the extra lumps of stuff in the pocket.

Materials & Performance

I’ve never liked the clammy way I feel inside sleeping bags. I either sweat and end up feeling wet and cold, or I’m just cold. Thus, I’m forced to always wear layers that absorb my sweat. I’ve never been comfortable in sleeping bags.

The beauty of the Nemo Rave 15 Sleeping Bag is in its breathability and high performance. The 30-denier nylon taffeta is comfortable next to the skin; the 650-fill Nikwax hydrophobic down manages perspiration; and the gills vent excess heat, stopping perspiration at the source and increasing the bags breathability.

A waterproof and breathable footbox “protects against tent-wall condensation,” as the brand puts it. I agree, the features work — I sleep better in this bag because I am warmer and drier.

Bag Shape

The spoon shape is awesome, and it is something Nemo developed in 2013 when it launched its sleeping bag line. Extra space at the elbows and knees allows for more natural sleep movement (i.e., it’s perfect if you toss and turn all night like I do). The bag is tapered at the waist to cut down on material, weight, and increase thermal efficiency.

Weight & Price

Because of the spoon design and modest 650-fill down, the bag has more material and is slightly heavier than other, similar bags on the market – 3lbs. 3oz compared to Marmot’s Helium, 2lbs. 2oz.; Western Mountaineering Ultralight, 1lb. 3oz.; and Mountain Hardwear’s Phantom, 1lb. 15oz.

On the other hand, it’s also $299-$319, while the other bags are all closer to $400. The extra material and good-but-not-exceptional down quality may not be ideal for minimalists who wants to go ultralight.

However, I want to sleep well, and this is among the highest-performing, most comfortable bag I have ever used. So I’m bringing the extra pound! On the other hand, I have not tested all those other bags (mentioned above); they are likely excellent performers. This is not a head-to-head review.

Aesthetics

The bag comes in two colors: Jade (outside) and Sea Green (inside) or Jade (outside) and Hot Pint (inside).

Nemo Rave 15 Review ($299.95-$319.95)

This isn’t the ultra-lightest of sleeping bag, but it’s an excellent water-resistant, breathable, warm and super comfy option for any backcountry adventurer.

Availability: Released spring 2017.

Buy Now: $299

Sizes:

Long (Fits up to 72in.; Shoulder Girth 60in.; Hip Girth 60in.)

Regular (Fits up to 66in.; Shoulder Girth 58in.; Hip Girth 58in.)

Interesting: The “blanket fold” is the coolest new feature I’ve experienced in a sleeping bag.

Flaw: Heavier than other similar bags.

First impressions: Incredibly comfortable.

Who should buy it: Anyone who sleeps outside.

Buy Now: $299

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