Few companies know more than Therm-a-Rest when it comes to getting a good night’s sleep in the backcountry. They’re renowned for their pads, but it seems like fewer people recognize their line of sleeping bags. I recently tested a heavy-hitting winter sleeping bag, the Centari, but I’ve since turned my sights ahead to the glorious summer of adventure that lies ahead. And with that comes the lightweight, three-season Antares HD down bag from Therm-a-Rest.

Therm-a-Rest Antares HD Features:

  • Zoned Insulation (Box-baffled 750+ fill Hydrophobic Down w/sewn-through insulated bottom)
  • Reflective ThermaCapture™ lining for added warmth without excess weight or bulk.
  • 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
  • DWR-Treated 20D Nylon Shell
  • Stuffsack and storage sack included
Therm-a-Rest Antares HD Review

The cut of the bag is fairly generous

Antares gets all the features

There seems to be two diverging schools of thought when it comes to sleeping bag designs. Some Northwest staples are still making ‘purist’ bags, simple designs with horizontal box baffles and no frills. Other companies are jumping on the technology bandwagon in creative ways, loading their bags with all sorts of features and perks. Therm-a-Rest, a brand with some very significant heritage, has been falling into the latter camp with their most recent bags. That, I want to argue, is a good thing.

The three-season Antares HD clocks in at 1lb 15oz. That is remarkably light for a bag in this temperature range; Therm-a-Rest places the Antares at 15’F as the male comfort limit. That’s pretty darn solid. Another comparable ultralight bag (of the no-frills category) that I tested a few years ago came to mind; it is decidedly in the no-frills category, and yet still clocks in at 3oz heavier. This is, in some ways, very strange. It doesn’t add up. The Antares is a full-featured bag (features add weight!) and yet is classes as ultralight. Perhaps the secret lies in the price tag – at nearly $500, this isn’t a cheap bag. There’s some serious design going on here.

One of the easiest places to see this is the zoned insulation that Therm-a-Rest employs. The bottom of the bag that your torso and upper legs rest on is stitched with a very light, sewn-through insulation pattern. It’s more difficult to manufacture than traditional horizontal box baffles, but the upshot is that you don’t waste weight in an area that’s just going to be compressed by your body weight. That also means that a good insulating pad is essential – see the Therm-a-Rest NeoAir I recently tested.

So what are some of the other features in this pad? Well, there are quite a few little ones, including liner tabs for securing an appropriate inner liner; another nice touch is the small shoulder-level pocket for valuables and things that tend to freeze. Most striking of all, of course, is Therm-a-Rest’s proprietary ‘SynergyLink’ system. This is essentially two elasticized straps that hold your sleeping pad onto the pad. This doesn’t sound like much, but they do an absolutely brilliant job at keeping you on your pad, allowing you to turn freely while staying on your nice, warm, cushy pad. Therm-a-Rest also included more traditional webbing tabs if you’d like to use some other strap system.

Therm-a-Rest Antares HD Review

Info on the draft tube. Note the tabs for securing a liner.

The zipper is a large, two-way affair that runs in an enforced, snag-proof track. I give it a middle B in terms of ease of use; it still gets stuck on, for example, the draft tube, but it’s doing as well as about any other sleeping bag I’ve tested. Mind you, I’ve tested a lot, and this is a difficult thing to get right. You’ll almost inevitably snag it every now and then. The zipper tops out in a generous zipper garage that makes for a cushy next-to-skin experience. As a matter of fact, that bag is comfortable around the face in general. The face and neck are adjustable via a pull cord in a friction lock; this works fine, though I wish they had used a wider-gauge, differentiated cord system. I found that I had to re-tighten the chest baffle on cold nights. This is, in part, because the chest baffle isn’t quite as generous as I would like; I felt like I had to fluff it up every now and then just to keep cool air from circulating.

The fit of the bag is generous overall, which is particularly noticeable around the legs and shoulders. I can turn freely in the bag, and there’s enough room to move my legs around. It’s definitely not as tight as a traditional high-performance mummy. On the whole, I like this – there’s obviously some penalty in terms of having ‘extra space’ to heat up, but since when is being warm the only component to a good night’s sleep? Obviously it’s a huge part, but you know what I’m getting at. A comfortable bag is more than just warm. So, with that in mind, I appreciate the extra mind in the Antares but I know that users with a minimalist bent will find it an exorbitant waste.

Therm-a-Rest Antares HD Review

The adjustment cords for the face and collar.

A lot of the testing that I did with this bag took place in the high desert. This was an excellent setting for the Antares. It had to deal with some moisture (not as much as it would have in the PNW) due to precip during the trip and condensation during cold nights. The DWR on the 20D fabric along with the Nikwax-branded hydrophobic goose down did an excellent job at managing moisture. Hydrophobic goose down is now the standard, and we’re all familiar with its benefits.

Nighttime testing temperatures were often in the mid-high 20’s. I began to feel slightly chilly in my midweight Patagonia baselayers around 25’F. That’s well above the bag’s 15’F comfort rating, but that’s consistent with how these temperature ratings often seem to pan out; you would expect to have to add more clothing layers to take this bag down to 15’F. That said, I suspect that part of the reason the Antares clocks in at such a light weight is because it might be slightly under filled for its temperature rating. This may be an intentional choice on Therm-a-Rest’s part; they stitched a thermally-reflective lining into the bag, which in theory will reflect radiant heat back at you. On the bright side, I noticed hardly any heat leakage out of the zipper track – the draft tube does its job well.

Therm-a-Rest Antares HD Review

Note the reflective lining, which is exposed in the zippered pocket

The Good

  • Very lightweight
  • All-in-all a great feature set
  • SynergyLink connects pad/bag and works like a charm
  • Generous cut is great for claustrophobic users

The Bad

  • May be slightly underfilled for its temperature rating
  • Hood/collar adjustments should have different cord

The Bottom Line: Therm-a-Rest Antares HD

It’s not a cheap sleeping bag, but it’s a good one. I was impressed by how packable and light it was, which you don’t always expect from a 750-fill bag. Therm-a-Rest knows how to make good sleeping gear and it’s great to see that being translated into a bag like this. Coupled with one of their pads, you’ve done about everything you can to get a good night’s sleep in the backcountry short of sleeping pills.

Buy Now: Available from Backcountry.com

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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