Therm-a-Rest NeoAir XTherm Pad

Pros: 

The NeoAir XTherm continues to be our go-to pad for winter camping. The lightweight pad is quite compact—it's on par with standard inflatable pads when packed into its stuff sack—but Therm-a-Rest's compartmentalized core construction delivers a best-in-class warmth-to-weight ratio. Therm-a-Rest segmented the XTherm's internal structure into rows of triangles, which serve as a buffer between warm body and cold ground, helping to mitigate heat loss. For those who like to nerd out on numbers, the XTherm has an R-Value of 6.9 (Therm-a-Rest recommends an R-Value from 4 to 6 for all-season use, and notes that R-Values of 6 or higher are more suited to extreme cold). With a thickness of 2.5 inches, this Therm-a-Rest pad is exceptionally comfortable. The WingLock Valve is a welcome feature, too: the valve style enables quick, efficient inflation and deflation.

Cons: 

We haven't had any problems with the XTherm so far. If we're nitpicky, the internal core construction makes the pad crinkly and noisy when tossing and turning, but that's a small price to pay for the warmth it provides. 

Bottom Line: 

The warmest and lightest pad we've ever tested for winter camping, simple as that.