I just don't think your ambients are coming from the RHP at least not 100% a few degrees maybe but not ten. I am not doubting you at all it just makes no sense.

If you place you hand in the enclosure not under or close to the RHP (with the RHP on) and move your hand toward it until it is directly under the panel there is a point where there is a marked and drastic temp change. Do you agree? Every panel I have seen this is exactly how it works. If it were heating the AIR the air beside the panel would be the same so the change would be gradual not dramatic. See what I am saying? Do you have a light in your set up?