I have one of those IR temperature measuring guns where you point its laser at a surface and it displays the surface temperature. Trying to check my cars a/c efficiency via the face vents, it was showing -4 to
-8C and possibly even colder. Obviously it is wrong - it cannot reach such low temperatures, so I added a thin strip of metal in front of the vent, but got similar figures. What is going on?
Is it the draft from the blower upsetting the reading or what? I have checked the accuracy and it is spot on.