Our experience with IR cameras brought me to this discovery:
I needed to see through a wall to see the studs in a 100 year old plaster and lath wall. It was easy.
Just put a radiant space heater on the other side to heat the wall. Then after an hour or so, use an IR camera to view the wall. You can see the studs and anything else that is inconsistent inside the wall.
Then I happened to glance with the IR camera at the wall where I had the 1500 W electric heater plugged in, and I could CLEARLY see the wiring in 3D. By moving the camera around I could see the hot wire in 3D and not only see where it was, but how deep or, along which wall in the pocket it was located.
I then went on an exploration mission in my basement to see hotspots in my entire electrical system. It was an amazing color display liken to XMAS.
Then I noticed a large, unusually bright spot from the basement looking up at the kitchen floor. I was concerned, since it should have been a part of open floor and there should not be any heat source there unless it was an electrical problem beneath the floor. I ran upstairs only to find a cat, sleeping on a thick rug, on a ceramic tile, on a ¾” underlayment, on top of an OAK floor, on top of ¾” tongue and groove subfloor.
That’s seeing a cat through 3” of solid wood, ceramic and a rug. Just laying there burning up cat food.
I think these cameras are under $500 and even have APPS on cell phones that can do it?
You wont be able to see though metal, but through anything else, maybe so. In fact, to perfectly mark the hazy images where I wanted to drill the hole to the stud, I used a small 1” square of aluminum foil. It has low emissivity and always appears DARK against anything else that is warm behind it. But also, notice that the aluminum foil is not only low-E, but it is also IR REFLECTIVE. So it can look very hot (98.6F) if you happen to be standing where the aluminum can reflect your body heat.
Bob, WB4APR