Thermograms obtained with an airborne infrared scanner are compared to ground level observations for a number of buildings. Single-family residences were studied as well as buildings at a university and at a middle school/high school complex.

The density of the images on the thermogram are determined using a precision densitometer. The ground-based observations ,include roof-surface temperature determinations with thermocouples and resistance thermometers, direct measurement of heat flux through roof structures, and an estimate of thermal resistance from a knowledge of the structural components and the insulation present. Comparison of the optical and ground-based measurements provides information on the potential of infrared thermograms for determining building heat loss and the thermal resistance of structures.