I began to read the posts about the infrared detection and I jumped in with both feet in my mouth. (I was tokin' up, getting ready to go swimming in the pool)

I am a professional thermographer, so I can answer your questions and come up with reasonable solutions for you, If I use my fuckin' head. <G>

I'm headed out the door again so I don't have much time right now. But I'll get back to this discussion later. Meanwhile, keep in mind:

1) Thermographic cameras and detectors can be "fooled". As I said, emmisivity is the key. (a stainless or aluminaumstack and chinaman hat will show much cooler than actual temp.)
2) Hot air has no emissivity, it can not be detected with infrared sensors. Just the plastic damper/louver will appear hot.

ttyl

Sho