Window A/C Units (Minutes, Cheap or Free)

If you're buying a window A/C unit, look for the Energy Star label. These should use less electricity than those without the label.

Window A/C units are less efficient in direct sunlight, because they have to fight the heat of the sun in addition to cooling the room. When you decide on a location for a window unit, make sure it won't be in direct sunlight if possible. If the unit has to be in sunlight, you might want to try to create a cover to block the sun.

Make sure you clean the filters regularly. Clogged filters lower the amount of air that can pass through them, so they have to run longer for the same effect. Once installed, use caulk or expanding foam to seal any air leaks around the device.

Once you have a Window A/C unit installed, you may have an unwanted side effect - winter drafts. Unfortunately, these devices don't always protect too well against the winter winds. If it's not too much trouble to remove, just pull it out and close the window. This shouldn't cost anything, but it will lower your utility bill.

If it was difficult getting the thing mounted in the window, the thought of removing it and replacing it every year may seem like too much trouble. Don't fret, there's an easier solution. There are insulating winter covers for both inside and outside the unit. Thermwell/Frost King, for example, sells both internal and external window A/C unit covers through Home Depot. A set of both runs less than $20. In addition to lowering your utility bills, the covers will protect the unit from damage during the winter months.