If a fan doesn’t sound cool enough and the idea of central air conditioning makes you fearful for your bank account, you don’t have to suffer silently in your sweat. A good window AC to the rescue! The main thing to consider when shopping for one is the size of the space in which you’ll be using it. A unit that’s too small won’t sufficiently cool a large room, while one that’s too big will leave a smaller room cold and clammy. For spaces of 100 to 300 square feet, an AC with a BTU capacity of 5,000 to 6,000 should work perfectly. Mid-size rooms of 250 to 400 square feet require an AC rated at between 7,000 and 8,500 BTU. Larger areas of 350 to 650 square feet will be best cooled with a 9,800 to 12,500 BTU unit.