Minneapolis Blower Door for conducting standardized air leakage testing of homes. This calibrated fan and manometer creates 50 Pascals (and other lesser pressures, depending on the test) of negative or positive pressure and quantifies the leakage of a home. This helps determine if your home has enough --or too much!-- air infiltration based on the location, size, and shape of your home.
Kane-May Carbon Monoxide Meter for conducting tests of carbon monoxide levels of ambient air in homes and in flue gasses and ovens. This calibrated meter measures the parts per million (ppm) of carbon monoxide to determine if there are backdrafting issues (spillage versus venting), incomplete combustion issues, or other issues relating to combustion that may be life-threatening.
Gas Sniffer for conducting gas leakage tests. This device is used by gas companies to locate gas leaks. Not only are you paying for the gas that may be leaking, but it is an explosion hazard as well.
FLIR B-2 Thermal Imaging Camera for locating the areas of missing insulation, air-sealing issues, moisture intrusion, and any other application that requires the location and measurement of surface temperatures. This device is used to capture radiometric (each pixel is a temperature reading) digital images and full-motion video.
...and lots of supporting technology including smoke-sticks, pressure guages, remote thermometers, and, of course, highly trained eyes and other senses.