Looking for thermal anomalies in a shower stall is tough thanks to the highly reflective surface. You can expect to get all sorts of great pictures of your own reflection. Since these are hard to sell to your client and pretty useless as well, here is an idea that just might make your life easier and more profitable.
Dr. Scholl’s Foot Powder is the answer. This powder has a high emissivity when sprayed directly on the tiles. The reflections disappear and that heat source behind the tile comes shining through. And when you’re done with the images, you have a ready source of water to rinse the powder down the drain.
Please note this solution can only be used in a safe shower. NEVER spray powder in a live electrical box.