Marmot Lithium Review

This is a seriously warm bag packed with high quality 800+ fill down. It does not have a waterproof fabric or treated down. So this is a traditional style sleeping bag that belongs in a tent rather than a snow cave or bivy under a tarp during the winter months. With that said, it packs in a solid amount of warmth for being only 2lbs 9oz. This bag also packs quite small, and this is due to the lack of a few features, as well as a thought-out minimalist design from the start.

Performance Comparison

Warmth

Sleeping in the Marmot Lithium is a great experience. The bag kept each tester warm and the hood was plenty comfortable. We did notice that the zipper baffle and neck baffle were integrated into one. This is clearly a weight savings measure and did not insulate as well as two dedicated zipper and neck baffles. Another thing to note on warmth is the existence of a second left-hand side zipper. The idea behind the second zipper is to allow you to do tasks while still in the bag. However, if the secondary zipper baffle is not laid flat against it, cold will seep in. Our testers only experienced this once in a handful of nights sleeping out.

Weight

The Marmot Lithium weighs in at 2lb 9oz on our scales. This is quite the low weight for a 0F sleeping bag and is a credit to the bag's ultra-light face fabric and minimalist baffle design. In fact, when we were taking pictures of this bag on a windy summit, the bag almost flew away! Marmot includes a stuff sack that is ultralight material as well. Overall, this bag is light enough for any human-powered cold weather mountain excursion.

Comfort

This is where the bag really shines. It blends a slightly tighter cut and a feature set that allows you to be more comfortable while in the tent. The second zipper can be undone, and you can sit in the bag with both of your arms out and your upper body (and even head if you want) inside the bag. This allows you to do all of the different tasks in the AM while still cocooned in fatty goose down. Brew up, pack up and then emerge from the sleeping bag ready to move. The comfort this bag provided was excellent was catching some sleep too, we just wish it had a dedicated neck baffle as well.

Packed Size

The Lithium is a very compact sleeping bag when packed. Either just stuffing it first into your pack or using a compression sack, the bag easily fits into our testers 45L ski pack for an overnight.

Features

Again, the feature set on this bag is excellent. The second zipper that allows you to stay in the bag and still do camp chores is a welcome addition. It also features a small zippered pocket for storing small items while you sleep. The hood is one of the best we tested, and easily swallowed up the smallest grapefruits and largest watermelon heads among the tester group. This allowed everyone to really maximize the warmth of the bag, and it ranks highly among our features metric because of this. What detracts from the bag is the lack of a dedicated upper neck baffle. This slightly reduced warmth as well.

Weather Resistance

The Lithium is not a bag you want to sleep out in the open with, especially if there is significant precipitation in the forecast. We love this bag for any time we use a dedicated winter tent or full coverage tarp system. With that said, it has a very effective DWR and works well to shed light moisture. The Pertex Quantum that makes up the shell fabric is 20d, which is a bit heavier than some ultralight bags and is indeed windproof. With such a great face seal, you can get by in windier pyramid tents and such without much hassle.

Value

A quality bag, the Lithium is a great value. It's ideal for winter camping and packs extremely small. If you find yourself venturing into really cold temps, there are better values out there, but in the Rockies, it provides plenty of warmth and a great feature set for the money.

Conclusion

The Marmot Lithium is an excellent bag for winter camping. It has a slightly tight cut and second zipper which allows you to stay in the bag while doing AM camp chores. The lack of a dedicated neck baffle did reduce its warmth metrics, but with such a perfectly executed hood, it still scored high marks in comfort and features. Buy this bag if you frequently camp in a tent while overnighting.