Theoretical work has illustrated that highly infrared, transparent plastic films are well suited for use as intermediate glazings when used in conjunction with a low emissivity coating. Prototype glazing systems that incorporate low emissivity coatings and Teflon films were constructed. The thermal resistance of each of these prototypes was measured using the University of Waterloo Natural Convection Apparatus. Simulation of the glazing systems was carried out using a two-band glazing system thermal analysis program called VISION. Comparison between measurement and simulation showed good agreement. It can be concluded that highly infrared transparent intermediate glazings can be useful when high thermal resistance is desired and that the VISION glazing system analysis program is useful not only for parametric and sensitivity investigations but can also be used with confidence to estimate U-values of specific glazing systems.Renewable Energy Branch of the Department of Energy, Mines and Resource