Zpacks 10 ℉ Sleeping Bag Review

After all the trips we took last year, I feel really hooked on wilderness camping and hope to keep taking my family deeper into the wilderness. To help facilitate that, I’m looking to lighten my pack, especially for some backpacking. As a big (ok, fat) guy, it’s not easy to find an appropriately sized, lightweight sleeping bag. Fortunately, though, it’s not impossible. I picked up a Zpacks 10 ℉ sleeping bag over the winter and thought I would provide a brief review.

Zpacks 10 degree bag in Ventum ripstop nylon

I ordered an X-wide, X-long 10 degree bag in the blue Ventum. The bag is reportedly 66 in. wide and will fit around the neck of someone 6’4” tall. I measure 56” around my shoulder and 5’10” tall, so I hoped this bag would provide just the right amount of room for me. As you can see from the pictures, it’s a hoodless bag, so I wanted a little extra length to be able to pull it up around my head. I think it would have been fine to got with the long, but I don’t regret the extra length as I can fit my head in the bag, although I find it a bit suffocating to do for more than a few minutes at a time. The total length of the bag is right about 6 ft laying relaxed and lofted, and I measured the widest part of the bag to be 66" on the inside. The final measurement I made of the bag was a loft of about 6", although it was difficult to get an exact measurement. I’ve never had a high-quality down bag, and I’m pretty impressed with how the 900 fill power down lofts in these bags.

Full length zipper option

Close-up of zipper at last baffle

The other options I went with on the bag include a full length zipper and a draft tube. The basic bag is designed to essentially be zipped quilt, and Joe Valesko (founder of Zpacks) suggest sleeping with the zipper under you so that a draft tube is not necessary. However, I wasn’t sure how I would like that as I have not used a quilt before and am a restless sleeper. So I ordered the bag to be more like a traditional sleeping bag. I did find it a bit difficult to keep the zipper directly under me, but I’m not sure these additional options were necessary. Another reason I went for the full-length zipper is that it can be opened from the bottom to act as a vent. I plan on using this bag for all but the warmest months, so I wanted to have some additionally flexibility. When the zipper was kept toward the bottom, I didn’t notice any drafts, but when it was on top, I noticed that the draft tube did not exactly cover the zipper. It’s not incredibly stiff and is fairly narrow, so it doesn’t give the best coverage of the zipper. Obviously, the upside is that it’s not heavy. The bag, along with the cuben fiber dry bag, weighs 30.5 oz, so remarkably, I was able to find a sub-2 lb, 3 season bag to fit my large body.

I used the bag two nights inside a double wall tent (REI Half Dome 4) on an Exped Synmat 7 LW with temperatures down to about 27 ℉ according to Accuweather. On the first night, I slept without virtually no insulating clothes on except for my Merino wool socks, and I ended up being more than warm enough by the end of the night. However, I did have a bit of trouble warming up after catching a chill the first night. It probably took me an hour to warm up, but I don’t think that’s the bag’s fault as my skin was quite cold when I climbed in. I started out with a Polartec balaclava but found myself overheating after a few hours. I suspect that with some insulating underwear or additional light clothing I would be comfortable in this bag into the mid to upper teens. I don’t think I would push it to 10 degrees without some additional layers, though. I did expect the bag to bit a bit warmer than it is, but I should note that I don’t really have my system dialed in for 10 degrees, so it’s hard to judge exactly. I can say that it’s warmer than my Big Agnes Summit Park 15 ℉ bag, so I’m pretty satisfied with its performance.

I was initially concerned with the ultralight materials used in the bag, but I’m coming around to think this is the way to go. Zpacks offers this bag in two ripstop nylon fabric options, green Pertex GL or blue Ventum. I emailed Zpacks to find out the difference, and Joe told me his gut feeling was that they were very similar. Shortly after that, Richard Nisley reported on backpackinglight.com that indeed they are quite similar in both air and water permeability.

One thing that really concerns me, especially as a canoe camper, is keeping my gear dry. Cuben seems almost too good to be true, so I wanted to test out the dry bag that came with the sleeping bag. I recruited my 7 year-old daughter to help me with an experiment, and we decided to stick the sleeping bag in the dry bag in the shower for thirty seconds to see if any water would get in. I stuffed the bag in, closed the velcro, folded the closure three times and buckled it. We directed the water spray on top of the dry bag and adjusted it a couple times to ensure the water had plenty of opportunities to enter the dry bag. After taking it out of the shower, we dried the outside with a towel and inspected the sleeping bag and dry bag. The sleeping bag was dry without any noticeable moisture. However, we did notice that the velcro closure was wet, so I don’t know how much longer it would have kept the sleeping bag 100% dry. Nonetheless, I’m pretty happy with the results and am confident enough to continue using the cuben dry bag in my pack. I think I’ll give it another test toward the end of the camping season.

 

Soaking the dry bag

After the shower

My initial impression of this bag is extremely positive, and I don't see much that's not to like about it. Probably the biggest downside to this bag was waiting the five weeks it took to receive it. Plus, any bag with 900 fill down is not cheap. The upside, however, is that the warm to weight ratio of this bag is amazing. There are obviously trade-offs for the ultralightness. For example, you give up a hood, but a hood is not always necessary, and when it's cold a fleece or down balaclava can be worn. Another trade-off is in the durability of the materials. Although the 0.7 oz/sq. yd. ripstop nylon is likely durable enough, it's not going to be as strong or abrasion resistance as a heavier fabric. Even the drawstring used on the Zpacks bag is an ultralight option; I think it's about 1.5 mm in diameter and seems adequate for its purpose, but it's definitely smaller and feels less substantial than drawstrings on some of my other heavy weight bags, which range from 3.5 to 6 lbs. I'm also not in love with the draft tube, but it does seem to reduce drafts, especially when the zipper is toward the bottom. 

Ultralight drawcord and cord lock.

I look forward to putting this bag to this test in the northwoods this year and hope to report back after dozens of nights in it.