Down is often considered the superior insulator when it comes to sleeping bags for backpacking or camping. But it’s not the best choice for every adventure or every adventurer. If you’re vegan, down isn’t since it’s harvested from dead animals. If you’re on a budget, down is prohibitively expensive. Or if you want a versatile bag that’s suitable for all types of weather, down doesn’t insulate at all when it’s wet. The alternative? Synthetic insulation. But synthetic ultralight sleeping bags are often few and far between since the material is a bit heavier than down. So what’s an ultralighter to do? Try one of these synthetic ultralight bags on for size, of course (to pack in your ultralight backpack and spread out inside your ultralight tent)!
Not sure what temperature sleeping bag you should get? It’s more complicated than you might think. Read about how to understand sleeping bag temperature ratings here.
Enlightened Equipment Apex: The UL Boss
Weight: 30.1 oz, 23.8 oz, 17.8 oz, 11.8 oz (regular size)
Temperature Rating: 20º, 30º, 40º, 50ºF
By far the most ultralight synthetic quilt on the market (basically the only ultralight synthetic quilt on the market), the Apex is our go-to summer and shoulder season quilt. The fabric is supremely soft and light (though there are a few different deniers available if you want a sturdier quilt), there are no stitched baffles so no cold spots where insulation is compressed, and since the insulation is in a sheet inside the outer fabric, it doesn’t bunch or shift.
The quilts are available in several temperature ratings, tons of colors if you’re willing to wait for a custom order, and come with pad straps so the quilt stays put all night. We’ve tested the 40º version on many backpacking trips over the years and it’s still the one we want to pack on every trip. Bonus: there’s an option available with a fully unzippable foot box, one with a permanently stitched footboy, and one that’s a smidge heavier that converts into a more traditional bag.
Therm-A-Rest Space Cowboy: The Happy Medium
Weight: 28 oz (regular size)
Temperature Rating: 45ºF
Minimalist where it counts but functional as all get-out, the Space Cowboy from Therm-A-Rest is one of our favorite lightweight synthetic sleeping bags for summer. It packs up small, is nice and light, but still has all the features we want in a bag, including a full-length zipper, cinchable hood, baffles, and removable pad straps that kept us centered on our sleeping pad all night (and we toss and turn).
It’s a simple bag, but effective. And for those who aren’t fans of a quilt, whether it’s because they want to trap more heat or like a mummy hood or whatever, this one is our second choice for ultralight backpacking adventures. The outer and inner fabrics are also made of 100% recycled materials (just not the insulation). It’s available in small, medium and long sizes.
Mountain Hardware Lamina Eco AF: The Cozy Cocoon
Weight: 30.7 oz, 38.4 oz
Temperature Rating: 30ºF, 15ºF
While it may be bigger and bulkier than some other options on this list, this bag designed for cooler nights spent outdoors is super cozy and made of premium materials, so if worth the weight on some trips. When I say this thing is soft as butter and pleasingly fluffy, I mean it. So when temps drop, I’m happy to carry it into the backcountry when I know I need something that will keep me warm.
Plus it’s undyed, which is super sustainable, made of nearly 100% recycled materials, and it’s PFAS-free. It’s also available (in a slightly heavier) 15ºF version. We’ve spent many nights camping and backpacking in this sleeping bag and it’s always a favorite for how comfy and cozy it is.
Honorable Mention
Sierra Designs Hamelin: The Multifunctional Powerhouse
Weight: 39.6 oz, 57.9 oz
Temperature Rating: 30º, 15ºF
While it’s not the lightest or most compressible on this list, this bag is a cozy, sustainable option worth a mention if you prioritize multi-functionality, warmth and good sleep over cutting ounces. After all, a cold, sleepless night isn’t fun for anyone. Fortunately, the Hamelin can probably prevent that. It fully opens to function as more of a quilt, has a two-way zipper so you can vent the top or bottom of the bag, has a half zip on the other side for venting or arm exit AND can be worn around camp like a cozy burrito thanks to a footbox zipper that allows you to walk around and snaps at the shoulders that keep it securely in place.
It has all the features you want in a bulkier bag, like a draft collar and adjustable hood, but for less weight. It’s also made entirely of recycled materials. There’s a standard and women’s version available for both the 30º and 15º versions.
Bottom Line
Synthetic ultralight sleeping bags and quilts aren’t always easy to find, but they do exist! Depending on your needs, one of these should more than fit the bill. So stay cozy out there as you wander on! And make sure to pair it with the right sleeping pad!
