In case you do not have a central AC system, you can save a lot of energy if you just cool those rooms you really need cooled, like your living area and your home office. And for achieving this a small window air conditioner might be a perfect solution for one or any these “strategic” rooms in your house or flat.
So if you live in an area which is not extremely hot (or cool), only cooling or heating the rooms you really need during the times of day when it gets too hot or too cold saves you a lot of energy compared to heating or cooling your whole house. Oh, and here is another trick to save energy costs:
Keep the doors in your house closed, so the air cannot move through the whole house. You will save a lot of heating/cooling. And this is especially true if you are air-conditioning only some of the rooms and not the whole house. If you left the doors between the rooms open, the AC would have to air-condition the whole house instead of the single room – designed for air-conditioning one room, it will fail and only waste energy in the process. So: Always close the doors!
Ok, but back to the small window air conditioner: This is a very handy alternative to a portable air conditioner to climatize a single room (make sure you get the right size –Btu – for the room size). So if this room you want climatized has a window, especially a small window, a small window air conditioner can be applied to undersized windows as small as 14 inches wide.
More info: Air Conditioning Repair Charlotte