There are certain seasons and certain conditions that require synthetic insulation. Wintertime in the Pacific Northwest is one of these times. I spent a month south of the Glacier Peak Wilderness at the beginning of this year and it reconfirmed all of my worst thoughts: wet days with freezing nights, if it gets above freezing at all. Condensation settling onto your bag as your breath freezes in a poorly ventilated four-season tent. Days of slowly watching your gear get gradually wetter, despite your best efforts, as the mist-like snow/rain settles down on all of your earthly possessions. These are all good reasons to consider a bag like the Therm-a-Rest Centari.

Therm-a-Rest Centari Features:

  • Zoned Insulation (Shingled eraLoft™ w/ sewn-through insulated bottom)
  • SynergyLink Connectors integrate your mattress for optimal comfort and efficiency
  • Heat trapping draft collar and full-length zipper draft tube
  • Differential cut maximizes loft
  • Snag-free zipper
  • Cinchable hood
  • External zip pocket
  • Silicone DWR-Treated 20D Nylon Shell
  • Stuffsack and storage sack included
  • MSRP: $209.95

Therm-a-Rest Centari Sleeping Bag Review

For those type-II fun nights

I’ve tested a Therm-a-Rest sleeping bag before, but it was one of their three-season bags prior to a re-design for 2015-16. I was stoked to get my hands on a heavy-hitting winter bag like the Centari, largely because winter bags are always a tricky proposition. You’re trying to balance weather-resistivity, warmth and weight. The Centari falls a bit to the heavier side of the spectrum at almost four pounds, but that is a fairly common weight for synthetic bags at this warmth rating. Certainly you can find bags on either side of this, and in virtually all cases synthetic bags will be heavier than down bags. So what do you gain with synthetic? We’ll, we all know the answer – they’ll save your butt when it’s wet.


The cut of Centari is on the generous side. There are pro’s and con’s to this. On the plus side, the extra room usually translates into a better night’s sleep because people like to have a little space to move around. On the down side, this means that you have more space to be heating up with your body’s energy. This is more noticeable in the footbox then anywhere else, so take heed if you tend to get cold feet easily. Overall I enjoyed the extra space, but that’s also because I have other serious winter bags that I bring with me on extremely cold trips where efficiency is top dog.

It’s easy to regulate the temperature of the Centari thanks to the 3/4 length, two-way zipper that Therm-a-Rest included. The tabs are big and easy to grab, a major boon if you happen to be trying to actuate them with gloves on or, let’s be honest, when you’re groggy for a 2am alpine start. The zipper track earns good marks from me – it’s not brilliant, but it usually pulls smoothly. Occasionally the large draft tube slops down and gets stuck in the zip, but generally the reinforced fabric area along the track keeps things in place for easy entry and exit.

Similarly, there’s a conveniently-designed drawcord system at the face of the bag. You can adjust the chest and face collars independently of each other, but unfortunately there’s no differentiating markers on the strings to tell them apart. Some brands will use different colors or types of pullcord, but Therm-a-Rest opted for the same narrow-gauge cord. It’s lightweight, but it also slips more easily than I would really like. At times I woke up to find that my nighttime thrashing had opened up the collar enough to chill me slightly. It’s not a huge issue, but I think a different cord would resolve it. The other downside to the thin cord is that it can dig into your skin if you pull them really tight and wind up stretching against them during the night. It’s definitely not ideal, but it’s not a dealbreaker, either.


Naturally, Therm-a-Rest coated the bag in a good DWR coating. This is an important factor, particularly in the wintertime. Condensation can be a huge problem in mountaineering tents, especially when you’re socked in with a storm. Conditions vary widely, of course, but I never have more condensation problems than in the wintertime. What’s more, there’s just more moisture around with snow getting into the tent and creating a little slick of moisture on the floor depending on the temperature. The DWR on this bag certainly helps, and it’s a good line of defense before the synthetic insulation kicks in and does what it does best. It’s a siliconized DWR (which are usually quite beefy) on top of a durable 20D fabric weave, ensuring long-lasting protection and performance.

Speaking of insulation, Therm-a-Rest uses zoned insulation to save weight on their bags. The bottom of the sleeping bag is lightly insulated, which makes sense since this is where you compress insulation the most when sleeping. It’s not doing any good when it’s smushed, so why not just take it out? That’s what Therm-a-Rest has done, which is fine, but it means that you need to have an insulating pad, no matter what. There’s not really any wiggle room due to the way they’ve zoned the insulation. Mind you, Therm-a-Rest pads have one of my favorite features in the industry: SynergyLink connectors, keeping you glued onto the mattress at nights. I find these hugely helpful in getting a good night’s sleep, but there’s no doubt that they add some extra weight. For me, it’s worth it – but ultralighters will scoff.

As far as compression, it's like most synthetic bags - bulky.

As far as compression, it’s like most synthetic bags – bulky.

Lastly, kudos to Therm-a-Rest for including a little pocket for stashing small valuables. My glasses thank you.

The Good

  • Basic features, like liner loops, pocket, zipper track and collar adjustments, are functional and present
  • Synergy Link system does a stellar job at keeping the bag smack dab on your pad
  • Zoned insulation saves some weight
  • DWR + synthetic combination makes for a bomber winter bag

The Bad

  • Zipper snags still happen occasionally
  • Collar cord adjustment can slip, dig into skin
  • A tad heavy, but not bad for the class

The Bottom Line: Therm-a-Rest Centari

The Therm-a-Rest is a full-featured winter sleeping bag at a good price. If you’re looking for something to keep you warm in the worst of conditions, it’s an excellent option that offers many of the perks of a more expensive bag.

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About Author

Kevin Glover is an outdoorsman living, climbing and biking in Spokane, WA. Originally from the Nevada high desert, he moved to the PNW for its mild winters and allergen-free summers. He has guided throughout the Cascades and Enchantments for Peak 7 Adventures.

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