Why does your bed pillow get warm? Basically, the heat generated by your head (remember you're 98.6 degrees and the room is probably 20-30 degrees cooler) is absorbed by the pillow and it ultimately causes you sleep discomfort. The proprietary cooling fabric of this Serta 233 Thread Count Summer and Winter White Goose Feather Bed Pillow keeps you cooler during the warmer summer months or perfect year-round if you're a warm sleeper. The other side of the pillow is a breathable 100% cotton cover which is great when it's a little cooler outside, or if you tend to keep the thermostat turned down a few degrees (save energy). This bed pillow is filled with the perfect amount of white goose feathers for a medium firmness, great for all sleeping positions.