Buying an Air Conditioner

• 1). Measure the length and width of the room you want to cool.
  
  
• 2). Multiply length and width together to give square footage. For example, if your room is 15 feet long and 20 feet wide, you would multiply 20 by 15 to get 300 square feet. If the room is connected to another room without any barriers between the two, you will need to find their combined square feet.
  
  
• 3). Measure the length, width, and height of the open portion of the window that you plan to put the air conditioner into. You will want a unit with dimensions at least a little less than these measurements.
  
  
• 4). Buy an air conditioner that fits your needs. Both physical stores and online stores will list specifications for their units that will give the actual units' dimensions, and the square footage they are capable of cooling efficiently.
  
  

Installing a Window Unit

• 1). Open the window and screen as far as they will open.
  
  
• 2). Place the unit in the window. There will be brackets on both the top and bottom of the unit. The bottom bracket should rest against the bottom edge of the window frame, on the inside.
  
  
• 3). Close the window so that the unit's upper bracket rests against the top edge of the window, again on the inside. You may need someone to close the window for you while you hold the AC forward. The unit should fit snuggly in the window without wiggling very much.
  
  
• 4). Extend the flaps on the sides of the unit so that the edges meet up with the sides of the window frame.