F or the last couple of years, I’ve only used quilts for backpacking. Once I transitioned, I couldn’t get enough of the extra room, versatility, and weight savings that I get with a quilt. When asked to review Therm-a-Rest’s new 20-degree sleeping bag, I closely reviewed the product’s specs and features first. I was immediately impressed. Even in the long version, the Ohm is even lighter than my 20-degree quilt, has about the same packed size, and packs a ton of features that make it a strong competitor in the highest echelon of ultralight sleep systems.

The Therm-a-Rest Ohm is an incredibly versatile ultralight sleeping bag. The regular version weighs just 1 lb 6 oz, and it packs down to roughly the size of a Nalgene. My biggest fear was sacrificing space and comfort while snoozing, but there is actually quite a bit of room in the hips and shoulders. Furthermore, for warm nights, the zipper extends all the way down through the footbox so you can fully open it into a quilt. In my opinion, albeit expensive, this bag is much more versatile than many competing ultralight sleep systems.

Hammock camping in the Wasatch. I apparently really like Therm-a-Rest products.

Enjoying a midday backcountry burrito in the Wasatch Mountains.

I tested the long version of the Ohm for the last few months of Utah shoulder season on a wide variety of different adventures. In the spring, I took it on an overnight backcountry ski trip and car camping in the desert. Now that the snow has (mostly) finally melted in the Wasatch range, I’ve been able to test this bag on a couple of overnights in the mountains. I’ve used it across a range of temperatures, from lows below freezing to waking up to a balmy 70-degree morning. Its versatility has made it an excellent new addition to my pack during these varied weather and multi-sport months.

A large reason why this bag is so lightweight, packable, (and expensive) is because of the quality of down insulation used. In short, sleeping bags and quilts that use this quality of down are lighter because less insulation is needed. The individual down plumes trap more air between one another, which keeps your warmer. So, a sleeping bag with 600 fill-power down will have to use more insulation (adding weight) than a 900 fill-power bag. In addition to weight savings, it also compresses extremely well.

Sleeping bags and quilts that use 900 fill-power insulation are the lightest and most packable options available. Because of this, they are also the most expensive. In my testing, I’ve been extremely happy with how well the Ohm lofts up out of the compression sack and then compresses again the next morning. I’ll be sure to store it long-term in a larger sack so it retains its lofting power over time.

READ NEXT – The Ultimate Guide to Backpacking Sleeping Bags and Quilts for All Budgets

One liter Nalgene for scale.

Warming up inside a ~25-degree Yurt (before we started the fire).

If I’m choosing to take a sleeping bag over a quilt, I personally would prefer to have a full mummy hood for cold mornings like this.

This zipper extends all the way around to the end of the footbox. Probably my favorite feature

This is the perfect shoulder season bag. It’s a bit much for the warmer summer months, where I can get by with an even lighter quilt. When it’s in sleeping bag mode, it stays quite toasty and is a bit too hot for anything over ~50-degree nights. Though it does convert to quilt mode, without a zippered foot box, I’ve really only found that useful for warmer weather trips and wouldn’t use it that way during shoulder season.

I can’t wait to use this bag for some late summer and fall adventures I’m scheming in Idaho and Utah. It’s absolutely perfect for high alpine shoulder season, where you want consistent warmth without extra bulk or weight.

If it’s in your price range, I would highly recommend this bag for thru-hikers expecting to encounter a variety of temperatures on their trips. When fully zipped into a sleeping bag, I’m cozy down below freezing. On the other hand, when converted to quilt mode, I can comfortably cowboy camp in the desert or use it for extra comfort around a campfire. However, if you prefer a full mummy bag with a lofty hood or want a more durable product, this may not be best for you. I’ve been a big fan of Therm-a-Rest products for years, and I’m very excited to have this bag for high alpine trips later in the summer and early fall.

The Therm-a-Rest Ohm was donated for purpose of review.

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Hi! My name is Katie (Gallon Smash) Kommer. I recently completed the John Muir Trail, and am already hungering to find my way back to my truest, stinkiest self. On the trail, I'm known as gallon smash for my exceptional ability to fall headfirst into a bush or a river, and in the "real world" I'm known as the recent grad who's trying her best, okay?