Feathered Friends Vireo UL Review

The Vireo UL has a few different design elements not found on any other sleeping bag in this review. It is the only mummy bag to forego a zipper completely. We love the unique variable fill: the bottom half of the bag is rated to 25°F, and the top half to 45°F. The idea is to use an insulated jacket you're probably carrying anyway to keep you warm at night. Because this sleeping bag is meant to be paired with a bulky jacket, the fit in the torso is one of the most spacious of any mummy bag we tested, and on warm nights, you can always sleep in this bag without the jacket at all, keeping your bottom layers thinned out as well.

Performance Comparison

Warmth

The Vireo UL has a variable fill of 25°F on the lower body and 45°F on the upper body. It is hard to discern the difference in lofting insulation between the two halves. To accomplish this, Feathered Friends uses 9.4 ounces of 950+ fill goose down, which is amongst the highest-rated down of any bag we tested. The baffles are horizontally oriented, rather wide, and sewn through.

While it doesn't have a hood, we still found this bag to be pretty warm, and the top does have a simple cinch to help with drafts. We tested it primarily while backpacking and camping out on climbing trips and found that on nights when the low temperature was in the 40s, we still felt comfortable without needing to add our puffy down jacket. On a colder trip on the Colorado Trail in October, we experienced the changing of the season, and we were happy to have a 1000-fill puffy.

In our hot water bottle overnight test, the Vireo came out more impressive than some 20°F rated bags, even with its 25°F-rated bottom. We feel that this rating is realistic or perhaps even generously conservative.

Weight

We tested a 74-inch long Vireo UL, which is the longest size available. Our test bag weighed 16.4 ounces, slightly lighter than the advertised 16.7 ounces, and the included stuff sack weighed an additional 0.8 ounces. This makes the Vireo one of the lighter sleeping bags in our test.

The high-quality 950+ goose down comes in at 9.4 ounces or 57% of the bag's total weight. A 10D shell and 15D liner don't add much to the overall weight, nor does the single top cinch. There's really not much fluff to this bag except for the feathers themselves.

Comfort

Since this is a hoodless mummy bag that is only meant to come up over the shoulders while being worn, the size choices are a bit short compared to most that we tested. For this test, we went with the 74-inch option. This length easily fit our head tester's 5'11" frame, comfortably coming over the top of the shoulders. While the legs and feet of this bag are quite narrow, the torso and upper body region are the widest and most spacious of most of the mummy bags we tested, significantly adding to overall comfort. This bag felt downright palatial when we didn't wear an extra jacket inside it. Even with a down jacket on, as it is designed to be used, the upper body is not too restricting.

With no zippers and only one single drawcord at the neck, there were virtually no features or cords on the Vireo that could annoy us while sleeping, helping it score near the top of our ratings.

Versatility

With no zipper or enclosure system of any sort, this bag isn't the most versatile. Not only is it a pain to wriggle in and out of, but it is literally impossible to ventilate built-up heat on a warm night. Used in the mountain setting as it is designed to, this shouldn't be a problem, but if you intend to stretch this bag's usage to camping at the base of a mountain or for simple backpacking trips, then it's a tad annoying.

The variable fill of this bag does add to the versatility a bit, as you always have the option of wearing an insulated jacket on cold nights or foregoing any extra layers if it's warm and they aren't needed. We also like how the outer shell fabric is made of naturally water-resistant Pertex Endurance UL fabric, lessening the chances of water being an issue in the mountains.

Features

With very few features, there is not a ton to discuss, except to say that the lack of features is what helps the Vireo achieve such a light weight — an enduring feature in itself.

We do like how the single cord at the head of the bag is made of static cord, as opposed to a stretchy bungee cord, and its buckle does a fine job of holding the cord tight. Like many of the other bags, we still had the complaint that the long cord, when fully tightened, dangles in one's face and near the neck.

Should You Buy the Feathered Friends Vireo UL?

The Vireo UL is a specialty bag designed with alpine climbing and fast and light missions in mind. Its variable fill is meant to take advantage of the insulation you are already carrying with you in the form of an insulated jacket, thereby saving weight. With no zipper, getting in and out may take a little practice. That said, the very spacious fit was among the most comfortable we tested. Overall, this is an adequate lightweight bag for backpacking and fastpacking during the shoulder seasons.

What Other Ultralight Sleeping Bags Should You Consider?

If the “no zipper” idea isn't working for you, Feathered Friends also offers the Feathered Friends Flicker 40 UL, a full-zippered quilt. The Flicker is all about versatility, but you'll pay a weight penalty in return. For another lightweight bag, consider the Sea to Summit Spark Ultralight 28, which compresses down incredibly well with the included compression sack and is perfect for small-volume backpacks. Also, look at quilts to get a similar warmth-to-weight ratio. The Western Mountaineering AstraLite is a serious quilt that forgoes a lot of the features found in many others to save weight.