A winter sleeping bag without a high R-value sleeping pad is like a sheep without wool. Without one, your body heat will be sucked into the cold ground. We recommend using a sleeping bad with an R-value of 5 or better. R-values are additive, so you can also use two sleeping pads, one stacked on top of the other to achieve a higher composite R-value. Many winter backpackers will carry a foam pad, which can be used as a seat when cooking or snow melting, in addition to an inflatable sleeping pad for comfort. When choosing winter pads, we recommend using ones that have been rated using the new sleeping bag standard, such as the Therm-a-Rest XTherm, which has an R-value of 6.9