Therm-a-Rest Saros 20 Review

Therm-a-Rest is deservedly known for making outstanding sleeping pads. Their sleeping bags, however, have yet to earn a similar reputation. We recently tested their comfy Saros and ultralight Hyperion models. Both are impressive but still a step behind our favorite bags in their respective categories. Read on to learn why the Saros missed out on a budget sleeping bag award.

Performance Comparison

Therm-a-Rest has mastered backpacking sleeping pads. However, they seem to still be figuring out sleeping bags.

Warmth

The Saros contains 39 ounces of synthetic eraLoft insulation. This amount is considerably more insulation, by weight, than most other backpacking sleeping bags. Unfortunately, however, this insulation doesn't make it considerably warmer than other backpacking sleeping bags. Its 20°F lower limit rating (EN) seemed accurate compared to other bags. This rating, however, doesn't set it apart from the pack. We consider both the Big Agnes Husted 20 and The North Face Furnace to be warmer.

EN tested bags receive three ratings: a comfort, limit, and extreme rating. Most users will be happy near the comfort rating. Staying comfortable at the limit rating usually requires a quality sleeping pad and good layering.

Weight

A consequence of this bag's ample insulation is that it's disappointingly heavy. On our digital scale, a size long weighed 3.84 pounds. This figure is more than double that of the lightest budget sleeping bags, like the Nemo Kyan 35 and Klymit KSB 35. It is heavy enough that we recommend the Saros primarily for car camping and only occasional backpacking.

Comfort

One thing this bag has going for it is its comfort. It has some of the roomiest dimensions of any mummy bag. We're also big fans of the 20-denier polyester taffeta fabric which manages to be glossy while still feeling soft. The Saros also has a foot warmer pocket to keep your toes cozy. The comfort could be slightly improved, however, if the hood drawstring were an elastic cord rather than a shoelace-like string.

Compressed inside its stuff sack, the Saros is still too big to fit across the bottom of this large 75-liter backpack.

Packed Size

Another consequence of this bag's ample insulation is its bulky packed size. Using an after-market compression sack, we weren't able to squeeze it any smaller than 15.5 liters in volume. This model is more than double the size of the smallest budget sleeping bags. The simple drawstring stuff sack that it comes with is also an unfortunate shape that won't fit horizontally across the bottom of most backpacks.

Versatility

The Saros features a ¾-length main zipper that's okay at venting excess heat. It also has a fluffy neck baffle that's good for sealing heat in on frosty occasions. The synthetic insulation can be relied upon to maintain its ability to insulate if it gets wet. This bag, however, would score a little better in versatility if it had a longer zipper or another way to let heat escape on warmer nights.

Features and Design

This bag has perhaps the most accessory features of any budget sleeping bag we tried. Some of these are useful, others not so much. Many of our testers, for example, consider the sleeping pad attachment system unnecessary, but thankfully, it's removable. The stash pocket, in contrast, is an accessory feature that we happen to like for keeping a headlamp or phone handy.

The Saros has a zippered stash pocket on the right side of the bag.

Finally, the foot warmer pocket is a polarizing accessory. Some of our testers were rather fond of it. Others found it entirely unnecessary and thought the additional insulation needed would be more useful closer to your core than your extremities. With that said, it's up to you to decide if a small sleeve to tuck your feet inside is desirable.

Best Applications

Due to this bag's substantial weight and bulky packed size, we can't recommend it for extensive backpacking. Rather its superior comfort is best enjoyed while car camping or on shorter backcountry overnights close to the trailhead. It could also be a great bag for activities where weight isn't a huge issue, such as rafting or horse packing.

Our review team believes the Saros is too bulky and heavy for long-distance backpacking. However, it's great for car camping or shorter hikes near the trailhead.

Value

Although the Saros doesn't provide great weight or packed size performance, it has high-quality materials and construction. Many of our testers found its accessory features a bit much, but there will be plenty of consumers that feel the opposite. For those that will fully appreciate its extra bells and whistles, it offers a decent value.

Conclusion

There's a lot to like about the Saros. It's undeniably comfortable and fitted with some clever accessory features. We are also impressed with the quality of its materials and construction. However, to supply this comfort and include these accessories, it becomes disappointingly heavy — so much so that we think it's too weighty for frequent backpacking. The Saros is still an awesome bag for car camping or short hikes, but you'll probably want a lighter, more packable bag for backcountry overnights.