People are always talking about making sure their central air units are running properly, how many people really pay attention to their window units? I learned some great tips over the last few years. You can improve the efficiency of your window unit (without hiring a HVAC guy). You want to be sure that the window has a tight seal around the unit. If there are gaps, the unit will have to work harder to keep the room cooler. Any other tips out there? Do you check your window units each year before using them?