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Marmot Helium 15

rated 4 of 5 stars
photo: Marmot Helium 15 3-season down sleeping bag

Just returned a Marmot Helium bag after two uncomfortable nights in the Wind River Range for cold spots in the hip and upper chest area. Based on my own personal experience I cannot recommend it.


  • Both a full length zip from bottom up to ventilate feet or top down for easy in/easy out
  • A hood zip that allows you to read or eat without the hood in the way
  • Comfortable and warm foot box
  • Comfortable and warm hood


  • Due to lack of a draft collar, condensation from breath collapsed down below my chin
  • Cold spot around hips; measured outside temp at 54 degrees, inside of bag at 70 degrees.

I purchased this bag as a replacement for my old reliable Marmot Lithium because, over the years, the down in the bag had seeped through the lining leaving cold spots.  

The Helium had great features with the full zip from top or bottom to allow easy ingress and egress and foot ventilation plus the partial hood zip to allow reading or eating without the hood interfering. It's great fit, compressed size, and weight was impressive, so I erroneously assumed that the lack of a draft collar was compensated by some waterproof treatment of the lining or the down below the chin to prevent collapse of the loft, insulation against cold to the upper chest. I was wrong.

I spent two uncomfortable nights in it in the Wind River Range. The first night I noticed that the down had lost its loft below my chin, no doubt due to condensation from my breath (bad design). More noticeable was that, sleeping on my side, my bum was cold. I reached down to feel the inside of the bag and it was cold to the touch.

The second night I used the temperature gauge on my watch to document the temperature. With an external temperature of 54 degrees, the internal bag temperature around my bum was 70 degrees. For a bag rated to keep me warm down to an external temperature of 15 degrees this was not remotely acceptable.

The merchant made every effort to convince me that the bag was correctly rated down to 15 degrees and there were no defects but that it was I who was defective; not acclimated to colder temperatures, inadequate calorie intake, perhaps more sensitive to cold temperatures. I am an experienced backpacker; none of these applied.

The vendor, in his efforts to not stand behind his product, revealed that the down could shift along the columnar pockets leaving areas of the bag without insulation. He actually demonstrated how this occurs to show me I could redistribute the down by hand.

The bottom line is this. I was sold a bag represented to keep me warm down to an external temperature of 15 degrees and I had a 70 degree internal bag temperature in the hip area at an external temperature of 54 degrees.

For those who face a vendor unwilling to stand behind a bag that you have used to find not living up to its rating I have this advice. Buy with a credit card. Merchants are bound by the Uniform Commercial Code which imposes an implied warranty, fitness for a specific purpose. More importantly, if you contest the charge with your credit card company, the vendor will be dealing with their own merchant services. I got my refund on the bag.

Source: bought it new
Price Paid: $400

Wide temperature range. Light. Warm. Roomy.


  • Wide temperature range
  • No side baffle
  • Light


  • No draft collar
  • No side baffle

I own several Marmot sleeping bags from the lightweight Hydrogen to the extreme conditions Cwm. The Helium is my all around favorite, the one bag I would own if I could only own one and the one I reach for most often.

In my experience, high quality down has a much larger temperature range than synthetics. The Helium has a design feature that maximizes this versatility that you will either love or hate. Most sleeping bags have a side baffle to prevent the down shifting from top to bottom. If you toss and turn a lot during the night or you dislike fussing with a bag to customize it to your nightly conditions, you may not like this as the down may shift in ways you don't appreciate.

However, I have used this feature for my benefit. I am able to sleep on my back at night while camping and I avoid tossing and turning. In addition to other advantages, this sleeping position and the lack of tossing and turning during the night allows me to shift the bulk of the down to the top of the bag or the bottom depending on the temperatures that are expected.

Most cool nights in the mountains I shift the down to the top and keep my self toasty even when the mercury dips well below freezing. My sleeping bag keeps me insulated from the ground.

Minor temperature adjustments are made with the zipper either from the top or opening up the foot area. However, in the summer when warm nighttime temps are expected, I can either shift the down to the bottom or simply toss the bag over me as a blanket.

Customizing the temperature rating of the bag in this way has allowed me to sleep comfortably in 60 degree temperatures and uncomfortably, but survivably, down to -10 degrees. If used correctly, this design feature adds enormous versatility to the bag. The reasonably generous girth of the bag will allow many to wear a down jacket inside the bag in the coldest conditions.

One possible drawback to the bag is the lack of a draft collar. This saves weight and material but compromises the comfort of the bag in very cold conditions. Of course, a draft collar would be overkill on warmer nights. In colder conditions, there are easy work arounds through the use of a VBL or a fleece jacket tossed around your neck though many would be bothered by the fiddly nature of that solution. In the very coldest conditions that this bag is designed for, a specialized bag with a draft collar would work better. Buy a specialty bag if that is what you are looking for.

The Helium is a jack-of-all-trades. Light enough for warm weather trips. Warm enough to get well into the shoulder season and beyond depending on your ingenuity.


Desert camping. Alpine and subalpine backpacking and mountaineering. Winter camping in the Rockies.

Source: bought it new
Price Paid: Not sure. Purchased it several years ago.

This is a lightweight, premium quality sleeping bag. It sets the gold standard for three season backpacking, especially for people in a down-friendly environment like the Rocky Mountains.


  • Warm
  • Well constructed
  • Top notch materials
  • Compressible


  • Could be lighter
  • Doesn't have a fancy water resistant shell

I've had this bag for several years, and it is still pretty much the same model. Why? Because it's hard to improve on a near-perfect sleeping bag. The bag is warm down to its 15 degree rating and then some. There are no cold spots and no drafts. That's what you pay for when you shell out three hundred dollars.

Fit is entirely subjective. I'm average height and average build, and the bag is cozy but not small. Entry and exit is standard stuff.

There is no moisture resistance in this bag - Marmot now offers a model with that feature, but I'm pretty sure my Helium will last me several more decades. I don't mind the lack of water resistance. It's a down bag, and backpackers have been able to keep down bags dry for years.

Don't get me wrong - water resistance isn't a gimmick - but it's not a requirement for any sort of outdoor activity. I suppose if someone was on the fence between a synthetic bag and down, it might be a very appealing feature. For most people? Just keep the bag dry.

Packability is excellent. High quality, compressible, warm down and materials that aren't bulky. Once uncompressed, the down puffs up just fine.

This isn't a sleeping bag for someone who likes fancy features. Sorry, it's just not. It just does its job in a way that isn't flashy. The bag is made to last a lifetime, but I usually take a sleeping bag liner because hey, it's a $300 bag.

This sleeping bag has been with me from New Mexico to Washington. I've spent countless warm nights in spring, summer, and fall in it. I suffer from chronic buyer's remorse with most gear purchases, but I've never regretted this one.

Source: bought it new
Price Paid: $320

Lightweight, super warm, 3-season sleeping bag. 15 degrees, super comfortable and warm 850 fill down. Best used for camping/backpacking in the fall/winter time. Definitely would recommend if you enjoy being warm and comfortable.


  • 15 degrees lower limit
  • Packs down small
  • 2 lb 3 oz — lightweight
  • Super comfortable
  • Comes with storage sack

This bag is really amazing, I've used it in the low 20s and it worked perfectly. I think the comfort rating is around 20 degrees and the lower rating is 16.

I spent 10 days on my sleeping pad only in the backcountry of Moab, Utah. I was wearing layers and warm hat, and a sleeping pad, but no tent. I also used a bag liner (just to keep the bag clean) the liner made it actually too hot once morning came. 

I have not experienced any cold spots or drafts. You can close the hood pretty far to keep the wind off your face if you cowboy camp. The length is perfect for me. I'm 5'10" with a little room to spare. Super easy to get in and out, the zipper is super long down the left side. The zipper does snag but every sleeping bag does, not a problem to me, you just have to zip any sleeping bag up slow and watch the baffle from getting snagged.

The shell does have moisture resistance and it works really well, I mean really well. I used the bag on another trip in Death Valley with a bivy and had so much condensation the bag was completely soaked on the outside, I was completely dry and warm on the inside still!

The bag packs down pretty small and fits perfectly at the bottom of my packs when storing. Once unpacked the bag takes starts puffs back up very easily. I have one small hole from a friend who was smoking a cigarette near my camping area, easily patched it with tape.

This bag is going to last me a very long time and I am extremely happy with it. I can't wait to push it to the limits this winter in the snow.

Source: bought it new
Price Paid: Bought with sale discount code, around $320

Nice materials, very light, looks well made. VERY slim fitting. I am 5'9" weigh 200 lbs, and it's not snug but it definitely is NOT relaxed. The zipper was difficult in the "wee" hours and tended to snag. I like the bag, but IMHO it's not in the same league as a Western Mountaineering bag. Sorry.


  • Nice fabric
  • Good quality down
  • Marmot name is great, they stand behind all their gear.


  • Didn't like the zipper.

Warmth, yeah maybe 15. I got a little cold on the bottom, but that happens.

Fit was too snug for my liking, no wiggle room. I know that adds to the warmth. Less air to warm. Exit was difficult. Like I said above, I don't like the zipper.

Moisture, didn't have that as an issue.

Packs small. Looks like it's well made. I looked over seams and they all look quality.

Had it about 2 months, used it twice. Honestly, I felt kinda let down.

Source: bought it new
Price Paid: $389

This is just a "first impression" of the Helium as I am returning it unused. This is a 2008 model, full zip. I find the "snag free" zipper and draft tube interface unsuitable. The zipper backing is too stiff and the tube too small. Though only a few reviewers have found this a source of cold spots I judged it to be inadequate and didn't want to stuck with an nonreturnable bag.

Other than that it seems to be a well made bag and the breathability of the shell material was superb. IMO, treated waterproof/resistant shells trap body moisture and make for poor down performance. In fact, I have a Sierra Designs 800-fill Trade Wind 15 with the so-called Dri-Zone that is worthless below ~27F. Also my opinion is that "snag free" zippers and waterproof coating are nothing more than marketing strategy or solutions in search of a problem.

I still have my old down California-sewn Trail Wise from 35 years ago and an Eddie Bauer expedition bag from nearly 40 years ago, both are untreated nylon taffeta (also an old Blue Kazoo).

Marmot needs to get back to basics and definitely improve the draft tube design. I live and hike in New Mexico with many side trips to CO, UT and AZ. Spring/Fall high country temps ~15F at night, very low humidity.

Design: Mummy
Fill: 850 down
Temperature Rating: 15F
Weight: 2lbs
Price Paid: $270

Great 3+ season bag for those with shoulders too large for an average mummy.


  • Warmth
  • Cut and comfort
  • Construction


  • Included stuff sack is not durable

I would say this is probably one of the best mass market, 3-season down bags available for the price. Lots of loft, packs down reasonably small considering it is actually rated to around 10 degrees for men (despite the name Helium 15), and the long version is very generously cut for guys with larger shoulders or those who wish to extend the temp range with additional layers.

I have yet to use near the limit, but so far have found it to be very comfortable from 20-65 degrees thanks to the long zip and additional quarter zip for bag venting. I am very particular about construction and durability of gear and I have no reservations about what Marmot did with this bag. 

Source: bought it new
Price Paid: $320

First off the most important question...Does the bag live up to its +15 degree rating?

Absolutely not. This bag is comparable in performance to most of your +30 degree bags. The loft isn't nearly as thick as I would like. All this comes as a result of trying to make a cold-weather bag out of a two-pound package.

The construction and stitching is well done. The shell is not that effective in keeping the down in. However this is my first down bag, so this could be the norm with down. It has a draft tube running the length of the zipper to help trap heat in. There are no frills as this is a minimal approach bag. It compresses down to a very small size.

I guess overall I am happy with the bag and for the most part has kept me warm. I just expected to be a little more toasty in a +15° bag put out by Marmot. The company has an excellent reputation so maybe I am one of the few who may be less than thrilled with what they got.

Design: Mummy
Fill: 800 fill down
Temperature Rating: +15
Weight: 2lbs 0oz
Price Paid: $300

This bag is awesome. It's light, compressible, big and warm. I have used this bag where it has gotten down to 7 degrees at night and I have always been toasty warm in it. Yes, it does live up to its +15 rating and surpasses it.

The only part of me that got cold was where the bag hit the bottom of the tent and where the sleeping pad did not cover there. So there is that to consider…cold weather camping requires a sleeping pad, but this is true with ANY down bag. I suspect the one negative review here was from someone unfamiliar with this fact.

All in all I am a big guy. 6 foot 1 and about 240 lbs. No part of the bag binds me like some others have. This is probably about the best full featured bag you can buy. Seriously. The only potential negative is the price…but hey you have to pay the most to get the best. Don’t forget this thing comes with 900 fill down. The best down available.

Design: Mummy
Fill: 900 fill down
Temperature Rating: +15
Weight: Just under 2 lbs
Price Paid: $350

I have primarily used this bag in northern summers, as an all purpose bag. I have spent two summers of trip leading sleeping it it all summer in Maine and Wisconsin/Minnesota, while also pushed its limits in October in northern MN and January in the Grand Canyon.

I recently got a Sea to Sumit 8L dry sack for it, which it fits in perfectly. These bags are not submersible, and take the place of the garbage-bag-in-a-stuff-sack combo in my pack.

The only time I've ever felt the cold in this bag was through my ground pad when I needed something more than a short 3-season Therm-a-Rest. My last night in the Grand Canyon I slept out under the stars and had ice form on the top of my bag and didn't know it until I crawled out in the morning.

Most recently I stuffed this bag inside my zero degree bag and slept out in -15 degree weather and stayed warm.

Design: left zip mummy

I'm on my third winter with the Helium. It's a great bag for sub-freezing nights, but much too warm for warmer autumn temps. I use a lighter synthetic bag (Kelty Lightyear 3D) for warmer nights in damp weather.

My coldest night so far in the Helium was 10F (-12C) and wearing only briefs and t-shirt I experienced no cold spots even rolling around a bit. I'm sure I could manage sub-zero temps in the Helium wearing mid-weight thermals or microfleece.

The hood can be cinched down to a small breathing portal if you're not claustrophobic. The cinch cords and zips can take a bit of dexterity to undo, but hey...what's the hurry on a cold morning?

Overall, I think the Marmot Helium is a serious moderate cold weather bag true to its temperature rating, light, small in your pack, and worth the premium price.

Design: mummy
Fill: 900 fill down (that's what the tag says)
Temperature Rating: 0F, -18C
Weight: 2lbs ~ 900g
Price Paid: $379 USD

This bag is very light, packs to nothing, features a half-zipper for weight savings, and a great, velcro-free hood system that just makes sense.

I've used it several times since I purchased it a few months back. Most recently I spent a 12 degree (F) night and stayed toasty (albeit I doubt it was 12 in the tent) even in just a t-shirt, polypro, and liner socks. I am not a warm sleeper and have been very pleased with this bag so far.

The DWR is great, and at my size (5'9", 165 lbs) the bag is quite roomy for an ultralight bag.

Oh, and the draft tube at the zipper is stiffened. The result: I can't make the zipper snag on the draft tube...even when I try!!

Design: Mummy
Fill: 800 fill down
Temperature Rating: 15 F
Weight: 2 lbs
Price Paid: $255 on sale

Awesome bag! Lightweight, warm, durable, compressible.


  • Warm
  • Lightweight
  • Durable


  • Need a summer bag—cuz this is warm

Just a great piece of equipment. Warm, durable, compressible, lightweight and covers three seasons well.

Inspires confidence: I know I can survive virtually any weather condition with this bag.

Can get warm in summer, so sometimes has to be unzipped!

Source: bought it new
Price Paid: $300

As the five star rating indicates, I seldom leave home without this bag. I've used it in temperatures hovering around zero and all the way up to 35 degrees. Invariably I'll throw this one in the car and make a final decision at the trailhead as to which to carry, but the Helium is almost always it.

It compresses down to the size of a cantaloupe using a compression bag, weighs next to nothing at just slightly over two pounds, and generally is warm enough for anything that I encounter.

Design: mummy
Fill: 900 fill down
Temperature Rating: 15 F

I previously owned a Western Mountaineering Apache MF (microfiber) 15-degree bag and it did not perform as well as this bag. The Helium bag is warmer, even though it has quite a bit larger cut (roomier), and it weighs less.

I can't think of anything bad to say about it. I would have given it five stars if the price was less than $40 or it weighed less than 1 ounce. Stellar bag.

Design: Mummy
Fill: 900 fill down
Temperature Rating: 15
Price Paid: $340

Just got back from a trip in the Black River wilderness in central Wisconsin, after sleeping a couple of nights in 2-foot snow drifts. The bag was awesome; any condensation on the bag the morning after was easily wiped up, with no noticeable decrease in loft after 2 consecutive nights in the high teens, wearing a thin fleece base layer and a hat to sleep. I slept with my wet clothes to dry them, and indeed, much of my gear came out dry the following morning.

I found the bag extremely comfortable, highly water resistant, very breathable, and ultra-packable. I've got mine in a small size Sea-to-Summit E-vent compression dry sack, and it comes in at around 11x7, or even smaller, if you'd like to squeeze it that much.

Bottom line: super-plush, 6+" loft, face guard seals perfect, cut is spot on...great balance between efficiency and elbow-room, and, most importantly, keeps you warm PAST its rating (conservative at 15). I have the model with 850 fill and pertex quantum shell fabric.

Design: mummy
Fill: 850 down
Temperature Rating: 15 F.
Weight: 2.0 lbs.
Price Paid: $360

I was so excited about my Marmot Helium—the weight, the fit, and the size of it. It worked well for me on the first few trips out and nearly for the first year. I began to notice that some feathers were coming out, although I couldn't find a hole. I called customer service, and they weren't much help. Told me to wash it and how, which I did, following their directions.

I took the bag on a trip in the Wind River range, into some 15 to 20 degree temps and spent all seven nights miserable due to the cold. I called again and sent it back to them, along with the money they required to wash it and add new down. After several weeks with no bag, I received it with two ounces of down added. So I was ready to go again...I thought.

On the next trip in February in West Virginia, I was warmer, but I woke to a bag soaked with water. My husband was dry in his bag beside me. I called Marmot again, and they told me to treat it with Grangers.

What good is their warranty? Useless for me. Waste of my money. I will be looking for a better bag and a better product than this.

Price Paid: $360

Had mine over 4 years now. Just hit 150 nights in it (6 washings). Dang bag looks new. Still as warm as ever when I need it and have managed to keep it dry.

I'm impressed enough to actually recommend it. Big price, but well worth it.

Design: mummy
Fill: down

Great bag, tougher then it looks, but was too warm for me.

Have only zipped it up once at 13,000 feet and would wake up sweating in the middle of the night anyway. Never knew I was a warm sleeper until I bought this bag.

Took this bag on a damp, lower Apps trip in 20 F temps. The bag was phenomenal!! Super light, comfortable yet the price is worth it on the trail.

Worth every penny. No regrets with this bag!

Design: mummy
Fill: down
Temperature Rating: 0-30f
Weight: 2 lb
Price Paid: $320

This bag is not unlike a supermodel. She's light and you wouldn't want to kick her out of bed on a cold night. This bag is amazing and it compresses to nothingness!

Design: Mummy
Fill: 775 fill down
Temperature Rating: 15
Weight: 2.0
Price Paid: $299

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The Helium 15 replaced the Marmot Helium EQ.


Regular Long
Price MSRP: $412.00
Current Retail: $47.99-$469.00
Historic Range: $2.00-$489.00
Reviewers Paid: $255.00-$400.00
Temperature Rating 15 F / -9.4 C 15 F / -9.4 C
EN Comfort 27.7 F / -2.4 C 27.7 F / -2.4 C
EN Lower Limit 16.3 F / -8.7 C 16.3 F / -8.7 C
EN Extreme -16.6 F / -27 -16.6 F / -27
Weight 2 lb 2 oz / 980 g 2 lb 6 oz / 1077 g
Fill Weight 1 lb 3.5 oz / 552 g 1 lb 5.5 oz / 609 g
Fill 850 Fill-Power Down 850 Fill-Power Down
Max User Height 6 ft 0 in / 180 cm 6 ft 6 in / 200 cm
Hip Girth 58 in / 147 cm 58 in / 147 cm
Foot Girth 40 in / 101 cm 40 in / 101 cm
Price MSRP: $389.00
Historic Range: $233.32-$398.95
Reviewers Paid: $360.00
Weight 2 lb 1 oz / 940 g
Fill Weight 1 lb 3 oz / 538 g
Temperature Rating 15 F / -9.4 C
EN Comfort 28.9 F / -1.7 C
EN Lower Limit 18 F / -7.8 C
EN Extreme -14.6 F / -25.9 C
Fill 850 Fill-Power Down
Shape Mummy
Max User Height 6 ft 0 in / 180 cm
Hip Girth 58 in / 147 cm
Foot Girth 38 in / 96 cm
Product Details from Marmot »

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