&gt; but any wavelength of light you absorb (not just IR) will heat you up<p>Thanks - this is the bit I was un-&#x2F;miseducated about. When we were taught about radiation in high school, I suspect my young mind concluded that since infrared and visible light were mutually exclusive on visibility, the same applied to heating. To this day, I thought infrared → heat  <i>and</i> heat → infrared.