These window air conditioners are made keeping in mind that the windows are double-hung ones. This is why you need to measure the AC unit and the window space available before you go ahead and purchase it. Placement of these window AC units is essential as this could be the factor that could hamper the lifespan of the device. Like the height of the ceiling, the number of doors and windows, the sunlight which might fall on the device, all this could affect the placement of the device.