ZPacks Classic Sleeping Bag 20 Review

The Classic is an overstuffed sleeping bag, wrapping you in 900-fill-power down in its vertical and horizontal box baffles. Just bring along a hat, as one of this sleeping bag's unique details is that it lacks a hood. The simple cinch strap and buckle make it easy to transform from “bag” to “quilt” mode depending on the conditions you encounter during the night. Weighing only 19.3 ounces (547 grams) with its included DCF stuff sack, the Classic makes a solid addition to your own “Big 3” ultralight loadout.

Warmth

With an impressive 13.7 ounces (388 grams) of 900-fill RDS Muscovy duck down – which accounts for 73% of its total weight – the Zpacks Classic 20 is a scorcher. It's given a somewhat unique 20°F “Transition” rating by the manufacturer, which deserves a little explanation.

The “Transition” rating is somewhere between the Comfort and Limit rating you see on most sleeping bags. But if you want to be conservative, think of it as the Limit rating of the bag – our tests prove that the Classic is as warm as 20°F Limit-rated bags with a similar fill weight and power.

One catch is that the Classic doesn't have a hood, so it's recommended to bring a separate insulated down hood or warm hat. Zpacks claims they overstuff each baffle with 30% more down than needed, which won't necessarily make the bag warmer but could help the bag maintain its loft and thus its temperature rating over time.

Weight

Weighing 18.8 ounces (533 grams) for the bag itself, with a 0.7-ounce (20-gram) stuff sack, the total package weighs 19.3 ounces (547 grams). This is about average for sleeping bags in the ultralight category across a variety of temperature ranges, but on the lighter end for bags at its warmth rating.

Several design decisions conspire to make the Classic as light as it is. The most obvious advantage is that this bag has no hood, which saves many ounces compared to a hooded sleeping bag. The 900-fill-power down lofts up more for the same weight than a lower-fill-power down, meaning less down is needed to achieve a similar temperature rating.

The liner is a gossamer 7D PFAS-free DWR ripstop nylon, which is among the lightest liner materials available. Even the included stuff sack is made out of an ultralight Dyneema. The Classic has a 3/4-length #3 zipper, which adds a marginal amount of weight but also adds a ton of versatility.

Comfort

Comfort is the Classic's raison d'être – what could be more comfortable than a sack of feathers to envelop yourself in? The warmer rating equates to more down fill, offering up a luxurious backcountry sleeping experience.

High-loft vertical and horizontal baffles leak less air than simple, sewn-through baffles. And within those baffles is the real good stuff – high-loft, 900-fill RDS Muscovy duck down. This high-quality down fill is what really keeps you warm, while still packing down tight.

Our 5'11" tester fit well in the “Standard-Medium” size, which is designed for people up to 6 feet tall. Zpacks offers a seriously impressive array of sizes, from “Slim-Short” to “Broad-Long,” to accommodate a wide range of body types and personal preferences.

Versatility

The Classic can function as both a hoodless sleeping bag and an open quilt. You can use this bag across a wide range of temperatures, which is important for trips that span many different environments, like a thru-hike of the CDT or the John Muir Trail.

Leaning on the hat, hood, or hooded jacket you're likely already carrying also helps cut down the overall weight of your kit. Thanks to the 3/4-length zipper, if you do get too warm, you can convert this bag into a loose quilt.

However, the zipper runs up the bottom center, which doesn't make it particularly easy to zip up or down when you're in the bag. On warmer nights, it was easier for us to unclip the head-end of the bag instead.

The footbox is closed, so you can't use this bag in full “blanket mode”, but you can get pretty close. We loved using the Classic as a throw blanket at camp, sitting around the fire at night, or brewing up some water in the crisp morning air.

Features

Like many ultralight sleeping bags we've tested, this one seems to lack features, especially for the big bucks you're paying. And it's technically true – the Classic sticks to the ultralight ethos of including only what's truly needed, with refined details that maximize performance while minimizing weight.

The Classic has a low-profile center push buckle and a cinch strap to snugly bring the head end of the bag around your neck. Curiously, what's missing are similar push buckles on the bottom side of the bag to optionally add pad attachment straps, which would make this a bona fide quilt.

The low profile center push buckle looks similar to a pad attachment strap buckle.   Credit: Justin Simoni

The simple and lightweight cinch found at the head-end.   Credit: Justin Simoni

The 3/4-length zipper near the footbox, unzipped.   Credit: Justin Simoni

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This bag is made from an extremely lightweight, non-PFAS DWR 7D Ventum Ripstop Nylon for the shell and liner – a material that's exclusive to Zpacks.

Should You Buy the Zpacks Classic Sleeping Bag 20?

The temperature range of the 20°F Transitional bag we tested works well for long trips like the PCT and the CDT, where extreme temperature differences are to be expected. However, because this bag is so versatile, it covers your bases for shorter trips, too – just as long as those shorter trips don't fall during the winter months. With an incredible range of offerings of different lengths, widths, down-fill options, and temperature ratings, there's sure to be a Zpacks Classic that's sewn right for you.

What Other Ultralight Sleeping Bags Should You Consider?