This vacuum cleaner is only for clean, but slightly dusty glass. To clean large glass and dirty, you need at least 4 approaches. For example, the window in the office is 3 by 2.2 meters. The robot makes one pass over it for almost 40 minutes. And you need 4 of them. Taking into account 2 sides, this is a colossal waste of time. In this case, the vacuum cleaner may stop spontaneously. squeak. Leaving him alone is unrealistic, as he can stop at any moment. Cleaned 5 office windows with it. It took almost a week. At the same time, all the edges are divorced and the corners are dirty. I do not recommend.