As noted earlier, reviews often recommend layering two closed-cell foam pads for winter insulation. Two closed-cell RidgeRest foam pads combine for 28 ounces of weight, with a total R-value of 5.2. You can also add one closed-cell foam sleeping mat to a three-season sleeping pad for extra insulation. The closed-cell pad usually goes underneath a self-inflating air/foam pad, but on top of a sleeping pad that's filled with air alone.
Insulated sleeping pads make the extra closed-cell pad unnecessary. Therm-a-Rest, Big Agnes, Exped and Pacific Outdoor all make widely recommended insulated sleeping pads. They all weigh more than a three-season sleeping pad, but two closed-cell sleeping pads generally weigh around 28 ounces, so the weight for a similar degree of warmth isn't much different. The insulated sleeping pads also compress better for packing than two closed-cell foam sleeping mats. Alternatively, adding a closed-cell pad to a full-length ProLite 3 three-season pad brings the total weight to 34 ounces.
More reviews recommend the 28-ounce Exped DownMat 7 (*Est. $140) than any other insulated sleeping pad. The 2.8-inch-thick DownMat 7 won the 2003 European Outdoor Award for its innovative use of 700-fill goose down. This insulates the air cushioning for a rating down to 1 degree F, with an R-value of 5.9. The stuff sack doubles as a pump. As is typical at Exped, the regular 28-ounce size is a somewhat short 70 inches long, so a tall person will need the 76-inch DownMat 7 DLX (*est. $155), which weighs 41.3 ounces. We did find one owner review reporting a leak in the air valve, but most reviews of the DownMat 7 are enthusiastic about this model.
The Exped DownMat 9 (*Est. $150) inflates to a thickness of 3.5 inches for superb cushioning, and it's rated down to minus 40 degrees F with an R-value of 8.0. The regular 70-inch length weighs 32.2 ounces – not much heavier than its competitor, the Big Agnes Dual Core (*Est. $105), but two inches shorter. The wider and longer Exped DownMat 9 Deluxe (*Est. $170) weighs 44.4 ounces. Both sleeping pads get top ratings from owners reviewing them at Cabelas.com, Altrec.com and Trailspace.com.
The self-inflating Exped SynMat 7 (*Est. $95) is 31.4 ounces, with 2.8 inches of cushioning. The R-value is 4.9, and testers for Outside Magazine report that it's warm down to "single digit" temperatures. The review at Backpacker Magazine is more conservative, rating it down to about freezing, but praises the cushioning as excellent. As with the DownMat 7, the regular pad is only 70 inches long, so taller hikers will need the 38.4-ounce DLX version (*est. $105) that's 26 inches wide and 76 inches long.
The 21-ounce Big Agnes Insulated Air Core (*Est. $90) is nearly as thick as the DownMat 7, inflating to 2.5 inches, but requires manual inflation. Air tubes are insulated with PrimaLoft, a synthetic fiber that's nearly as light as goose down, but much more moisture-resistant. (It's also 50 percent recycled.) Big Agnes rates this sleeping pad as warm down to 15 degrees F, and it won the Backpacker Magazine Editor's Choice award in 2004 for its combination of light weight, cushioning and insulation. It comes in three lengths and in both rectangular and mummy shapes.
The new 26-ounce Big Agnes Diversion (*Est. $90) is similar, but uses more recycled materials, including 100 percent recycled synthetic Climashield HL Green insulation. Even the nylon fabric cover is totally recycled. The main drawback to both these Big Agnes sleeping pads, however, is that they require manual inflation, and from what testers and owners report, occasional repairs. (They come with a repair kit.)
The 31-ounce Big Agnes Dual Core sleeping pad (*Est. $105) is also 2.5 inches thick, but it's self-inflating and uses a heavier 70-denier fabric for the cover for more puncture resistance. The Dual Core is a hair lighter than the regular 70-inch Exped DownMat 9, and it's two inches longer to boot. Foam is added to the tubes of air and PrimaLoft insulation, bringing the temperature rating down to zero degrees Fahrenheit. This innovative combination won the 2006 Editor's Choice award at Camping Life magazine. Rectangular and wider Dual Core sleeping pads are available, but of course they add extra weight; for example, the 25-inch-wide pad weighs 41 ounces.
Still, despite their innovative and award-winning designs, we found so many reports of leaks in Big Agnes air-filled sleeping pads that they dropped out of consideration, especially when a comparative review at Backpacker Magazine reported a leak that the repair kit couldn't fix. Users say that Big Agnes cheerfully exchanges leaky air mattresses for new ones during the warranty period, but that's not much comfort if you're in the middle of a camping trip.
The new Therm-a-Rest ToughSkin (*Est. $120) builds in a layer of closed-cell foam for a total R-value of 5.2 – as warm as two closed-cell foam sleeping mats. Tests at both Outside and Backpacker magazines confirm that it's highly puncture-resistant. The drawback is its weight, since even the 20-inch-wide version weighs 40 ounces. It's only 1.5 inches thick, and for this much weight you can get a lot more insulated cushioning.
The self-inflating 27-ounce Pacific Outdoor AO Aero Mtn (*Est. $120) is also only 1.5 inches thick, but uses a layer of high-tech aero-gel under the torso. Testers at Backpacker Magazine report that the aero-gel is such a good insulator that the pad itself felt warm even on nights below freezing. Two women's versions are also available, in 72-inch and 66-inch lengths.