Can you imagine every window in a building capable of generating electricity from sunlight and interior light? The technology has been developed and is ready for marketing. Check out this link. http://inhabitat.com/revolutionary-transparent-solar-cells-could-produce-50-times-more-energy-than-conventional-solar/ Also take a look at the companies website. https://solarwindow.com/ I can see it now. The electric squeegee will give you more energy! If you check out the diagram you will see the PV coating is on the inside of the IG units. But the glass will still need to be cleaned both outside and inside for maximum effect.