Much automotive glass filters (reflects) IR, and also absorbs UV. Each UV ray is "higher energy" but the sun pumps out vastly more IR than UV. You cannot imme

Much automotive glass filters (reflects) IR, and also absorbs UV. Each UV ray is "higher energy" but the sun pumps out vastly more IR than UV. You cannot immediately feel the UV on your skin, not until it gives you a sunburn. You are feeling the IR that was previously blocked by the automotive glass. Interestingly, glass on military vehicles generally does not filter IR. You need IR if you ever want to use nightvision equipment.