Marmot Helium Review

The Marmot Helium is a 15 degree down backpacking sleeping bag with winter temperature ratings that packs a lot of warmth for its weight. The 800+ fill goose down keeps weight down without going over the top on price.

The 20d inner shell reduces weight while the 30d outer shell increases water resistance and improves durability and longevity.

Coming in at almost 2lb’s (935g), the Marmot Helium is hard to fault, checking a lot of boxes for us looking for an ultralight, winter sleeping bag that can also fit into a small compression sack.

Marmot Helium 15 Sleeping Bag

Warmth

The Helium is rated to 15f degrees and performs well down to around 20f without the need for added thermals. Below that you’ll need to add some thermal layers and maybe even a reactor sleeping bag liner. Provided you don’t try to push things past that, the helium will serve you well in your winter adventures.

Weight

I was actually kind of surprised to see this bag come in almost cracking below 2lb’s, the Helium has some solid materials and a few features you really don’t see at this weight range. Any lighter and you’d need to start looking at quilts – i.e. cutting it in half. And, yes, there are lighter sleeping bags out there, but they tend to use 950+ down which adds an extra $100 or $200 depending who you go with.

The Helium manages to also strike a balance with the shell fabrics going for something in-between stupid light and bomb proof, as long as you take care of this bag – it will take care of you.

Comfort & Sizing

The Helium has an absolute boatload of space in the upper portion of the sleeping bag, very nice for sitting up in your tent or around camp, the foot box is a bit more constrictive but that’s something I’m willing to give up for toasty feet all night long.

Marmot Helium Packed Size

The Marmot Helium packs down super small. You can get by with a 10L compression sack but I’d suggest going for something a little bigger for ease of packing – you can still compress down smaller than 10L.

Marmot Durability

Marmot produces some of the longest lasting sleeping bags I know of. I’ve had a Marmot trestles (synthetic) since my teen years and its still a great bag – although its lost a lot of warmth as the synthetic fibers broke down.

With the goose down filled Helium you don’t have that problem and the bag, with care, will last a very long time indeed.

Marmot Helium vs the Sawtooth

The Marmot Sawtooth is like the cheaper little brother of the Helium. Sporting 600 fill power duck down down and an 30d ripstop nylon shell it is almost one full pound heavier.

Check out this video on the differences between down and synthetic:

Marmot Helium vs Never Summer

The Marmot Never Summer is a warmer and much more bulkier version of the Helium. It’s a similar design but makes use of much more and lesser quality 600 fill power down feathers. Depending on your climate and expected weather forecasts, choose accordingly!

Marmot Helium vs Plasma

While Marmot Plasma is a little bit lighter and a little bit less bulky than the Helium I find the 875+ fill to be too little of an improvement to justify the price jump. I suggest either sticking with the Helium for your winter bag – its very good – and getting something in the 950+ fill power range for three season. I just can’t justify the Plasma over the Helium.

Marmot Helium vs Kelty Cosmic Down

Kelty’s Cosmic Down is a much cheaper option than the Marmot Helium but personally I shy away from recommending kelty products. They certainly have their niche, time, and place but they are generally cheaper for a reason. I personally trust marmot a lot more with its temperature ratings.

The Verdict

At around $400, the Marmot Helium is one of the more expensive marmot sleeping bags in its temperature rating range. But for what you get, I can’t really blame them. 850 Goose down, isn’t cheap and $400 is still a far cry less than some of the ultralight options out there.

The few downsides make this a solid choice for most people and I know you’ll be happy with it for many years.

Could it be lighter? Probably, but you would either have to lose some creature comforts in the shell (like space), or lose some down fill making it less warm overall?

I believe the Marmot Helium strikes a meaningful balance between affordability and features without skimping on quality.

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