You are NOT measuring heat at the place the laser hits but an area that increases with distance.
Check the docs of your device. Mine reads at a 12:1 ratio circle that expands with distance like an invisible cone. Mine has a diagram on the side to give the area of the circle as distance increases from the unit. Get close on a ladder to read temps at a distance.
Reading Tamps
Re: Reading Tamps
Thanks. I had no idea