Reviving an old thread in a search for thermal imaging;
I found this in a web search on the off chance there was a usable app for smartphones (yeah a long shot but it was late at night when I had the idea)
Smartphone Thermal Imaging Attachment Becomes a Reality
According to their website they're not due until August;
$160 for a kit & $195 for an assembled unit.
IR-Blue Kit | RH Workshop LLC
I would be interested to see if it was any good to find air leaks and thermal bridges in a house.