So you've decided you need a portable air conditioner, or an air conditioner for a room in your house. What kind should you get? What size? What does 10,000 BTU mean? Here are some tips for finding the right portable air conditioner for you.

• Do a little work before you buy anything. An air conditioner that's smaller than you need won't keep you cool. On the other hand, air conditioners use lots of electricity, so one that's bigger than you need will cost more in the long run.
• Decide whether you want a window unit or a portable air conditioner. Window units are a bit more efficient, but you need a window to mount them. Getting a good seal for window units can be tricky, and they might be drafty.
• You'll need to measure the size of the room you want to cool. A rough estimate is okay. Take note of other factors, like how drafty the room is. If the room doesn't have a door, you'll need more cooling. You may need a bigger air conditioner if you're cooling a kitchen or other room with an appliance that heats up.
• Air conditioners' cooling power is measured in British thermal units, or BTU. This number is printed on the air conditioner packaging, and it's the number you need to look for to find the right portable air conditioner for the size room you want to cool. As an estimate, you'll need
  • 5,000 to 6,000 BTU for a 100 to 250 sq. ft. room,
  • 7,000 to 8,000 BTU for a 250 to 350 sq. ft. room,
  • 9,000 to 10,000 BTU for a 350 to 450 sq. ft. room, and
  • 12,000 BTU for a 450 to 550 sq. ft. room.
  Again, if you're cooling a kitchen or drafty room, you might need more power. If you live in a place with very hot summers or have a room in direct sunlight, you might need more power. If you have a shady room or just use the air conditioner to cool one room of a house that's already air conditioned, you might need less power.
• Window unit air conditioners tend to be more efficient than portable air conditioners, so you'll probably need a bit less power.
• Air conditioners also dehumidify air, so take that into consideration when evaluating different models.

Putting a little thought into your choice will save you time, energy, and money when choosing a portable air conditioner. Have a great summer!