Most window washing services will take an average of 15 minutes to clean a standard-sized window. However, the time it takes to clean a window can vary depending on the size and number of windows and the level of dirt and grime that has built up. For example, if a window is very large or has several panes, it may take longer to clean. In addition, if the windows are located in a particularly dusty or dirty area, it may take longer to get them sparkling clean. In general, Sparkly Clean Windows in Northern Utah should be able to clean a standard-sized window in 15 minutes or less.