A system for evaluating performance of a vehicle window defrosting/defogging apparatus includes at least one computing device having at least a processor and a memory, and one or more imagers configured for obtaining images of one or more windows of a vehicle. The processor is configured to execute instructions for analyzing the images to determine a defrosted/defogged portion of the one or more windows at predetermined time intervals, including controlling illumination to optimize the system's ability to distinguish cleared window areas. A graphical user interface is configured for displaying and/or manipulating at least one of the one or more images, digital data of the one or more images, and a predetermined template for determining the defrosted/defogged portion of the one or more windows. The system includes instructions for aligning the one or more images with the predetermined template, including processing the images to correct for window taper, curvature, and size.