An air conditioner offers a great way to keep your home cool in hot weater. To find the best air conditioner for you, you'll first have to determine how much space you need to cool. An air conditioner's cooling power is measured in BTUs, which will tell you how large an area it will cool. For example, a 5,000-6,000 BTU air conditioner will cool 150-350 square feet, while a 13,000-21,000 BTU air conditioner will cool 950 to 1,200 square feet.
You'll also have to decide whether you want a window air conditioner, a wall-mounted air conditioner or a portable air conditioner. Window air conditioners are fairly easy to install and usually cool 1-2 rooms. The best model for you will partly depend on whether you have vertically or horizontally opening windows. Wall-mounted units are a bit more work to install and usually require either a built-in box or brackets, which are screwed into the wall. Portable air conditioners require minimal installation and can be easily moved from one room to the next.