Self Cleaning Glass

Windows that wash themselves have long been the dream of building owners, and thanks to the clever folks at PPG Industries and Pilkington North America, self-cleaning glass is now a reality. How do they work? A thin coating of Titanium Oxide is applied to the exterior of the window glass. This coating does two things: first, it reacts with ultraviolet light to break down and loosen dirt. Second, its hydrophilic (water-loving) qualities make rain and other water-based liquids spread out evenly across the glass, carrying away particles of dirt. So is there reason for window cleaners to feel jealous? Are we about to be jilted? Fortunately not! While PPG’s self-cleaning glass, SunClean, and Pilkington’s Activ are both selling well, they’re not likely to corner the market anytime soon. Their Titanium Oxide coating is not without limitations. Ultraviolet light striking the glass only breaks down organic dirt, so rust and mineral deposits will likely remain a challenge for window cleaners. Additionally, buildings in areas with low rainfall, or with windows shielded from the rain, will require a little outside assistance to be truly clean. There are other considerations that indicate window cleaners will be employed for many years to come: self-cleaning glass currently costs 10-20% more than regular window glass. And even without this additional cost, owners of large, existing buildings such as One Nationwide or the Riffe Center are unlikely to want to replace all of their windows to save a relatively small amount on window cleaning!

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