R-value: how warm is a sleeping mat?
The R-value tells you how well a mat insulates you from the cold ground. Since 2020 all big brands test with the same standard (ASTM F3340), so you can compare mats of different brands. A rough guide:
- R 2 or lower: summer and warm nights
- R 3 to 4.5: three seasons
- R 5 and higher: winter and camping on snow
The Thermarest NeoAir XLite NXT has an R-value of 4.5 at 360 grams for the Regular, the XTherm NXT 7.3 and the Z Lite SOL foam mat 2.0.
Air mat or foam mat?
An air mat is thicker, more comfortable and packs small. It can puncture, so take a small repair kit along. A foam mat never fails and you can use it as a sit pad during breaks, but it is bulky. In winter many hikers combine the two: the R-values of the mats add up.
Which Thermarest mat?
- NeoAir XLite NXT: the three-season choice for most hikers, light and warm for its weight.
- NeoAir XLite NXT Max: the same mat in a rectangular shape, with more room for your knees and elbows.
- NeoAir XTherm NXT: for winter and cold shoulder seasons.
- NeoLoft: thick and comfortable, for when sleep matters more than grams.
- Z Lite SOL: the classic folding foam mat.
Inflate without breath
When you blow up a mat with your mouth, moisture from your breath ends up inside. The Alpenblow from Alpenglow inflates your mat in a minute and weighs only 8 grams. With the expansion pack it also fits older Thermarest, NEMO and Klymit valves.
Frequently asked questions
How much R-value do I need?
For summer trips R 2 to 3 is fine, for three seasons in the mountains R 4 or more. If you sleep cold, go a bit higher.
Does a sleeping mat work with a quilt?
Yes, and with a quilt your mat is even more important, because the quilt does not insulate below you. Use pad straps to connect the two. Have a look at our quilts.