Two Ounces to a Warmer Butt: Therm-a-Rest Z Seat

December 11, 2017

When you’re out in the winter cold, one of the fastest ways to lose body heat is to come into contact with a cold surface. Physics being physics, heat will begin flowing from the warmer object (you) to the colder object, a process known as conduction. And more often than not, your rear end is the chilly recipient of this process whenever you pause to rest and sit on a cold rock, log, or other freezing object.

To avoid a chilly behind, you can either stay on your feet the entire time (no fun on a longer outing) or carry a lightweight insulated sit pad. I recommend the latter. Closed-cell foam pads are the way to go here—they are durable, instantly ready for use, and don’t require you to inflate and deflate them every time.

If you’re out winter backpacking, a three-quarter length (48 inches) or full-length (72 inches) pad is a great option—it can serve double-duty as  both a sit pad and an extra insulating layer beneath you at night—but if you’re only out for the day, you need much less pad for coverage.

Enter the Therm-a-Rest Z Seat ($14.95), a 2-ounce, 13-by-16-inch folding pad that provides more than enough insulation to protect your rump from a sit on the snow or other cold surface.

A baby cousin to the Therm-a-Rest Z Lite, (which I’ve raved about previously), the Z Seat has the added advantage of folding up tighter and smaller; the folds are a short 2.5 inches apart as opposed to the five inches on the Z Lite pad. Once folded up, the Z Seat compacts to a tidy 12-by-2.5-by-2.75 inches that is easily strapped to the outside of your pack for ready access.

The Z Seat is also available with or without a “ThermaCapture,” which is essentially just a reflective surface on one side that helps minimize radiant heat loss (pictured above). While it doesn’t really add that much extra warmth, it certainly doesn’t hurt either—I would choose it given the option.

A range of other insulated sit pads are available, but few offer the combined convenience, light weight, and packability of the Z Seat.

Stay warm out there!


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Matt Heid

Equipped blogger Matt Heid is AMC's gear guru: He loves gear and he loves using it in the field. While researching several guidebooks, including AMC's Best Backpacking in New England, he has hiked thousands of miles across New England, California, and Alaska, among other wilderness destinations. He also cycles, climbs, and surfs.