A few quick words about R-value.
A few points to remember about EXPED mat warmth:
- R-value is the measure of an insulating material's resistance to heat transfer
- Higher R-value resists heat loss better resulting in a warmer sleep experience
- Exped mats currently range in R-value from 0.7 (AirMats) to 9.5 (MegaMat)
- In general, mats with R-values of 4.5 or greater are winter capable
- AirMats are a lightweight and compact choice for environments where cold nights are rare
- Warmer mats (higher R-value) reduce heat loss to the ground, leaving the sleeping bag to control convective and radiant heat loss.
- When a warm mat is used, people are surprised how much better their sleeping bag works. In reality, the bag was doing it's job well, but heat was being sucked into the ground before it could be trapped by the bag
- All Exped R-values are determined by independent Swiss government testing labs