A little over a year ago, DIYTripods featured a technique for taking heat-sensitive long exposure photos using a modified flashlight. The photographic process behind this is explained there. This gave me an idea that one could use a Black & Decker TLD100 Thermal Leak Detector (Amazon) without modification to do the same thing.
The unit functions pretty simply. You turn it on pointed at whatever you want to appear normal temperature-wise, and it displays green. Point it at something cooler and it becomes blue; point it at something hotter and it becomes red. To make an infrared image, photograph your target while slowly sweeping the red-green-blue beam across, and you have a crude infrared photograph. Between 25 and 30 seconds of exposure seems to work well for me.
The one thing that is kind of tricky is that the color transition isn’t instantaneous, but it’s not impossible to work around. In addition to what’s above, I’ve taken some other interesting photos using this technique, as seen after the “read more” link.
The window photo is probably the most interesting, as it shows where heat is leaving the house. This is, I suppose, what this IR gun is meant for, and maybe I will actually use it for that purpose at some point. For now, thermal long exposure photography is a neat trick!