Air Conditioners

Nothing can refresh you on a hot afternoon like the icy blast of an air conditioner. It's important to get the right air conditioner for your space, however -- too little power and the unit will be overtaxed and inefficient, and too much power will make your air too cold for comfort. Meanwhile, an inefficient unit will hog power and drive your electric bill sky high. Finding the right one is just a matter of a little research and familiarity with the basic specifications common to all air conditioners.

Cooling Power

  • Air conditioner cooling capacity is measured in Btus (British Thermal Units).
  • An air conditioner's price is closely correlated with its Btu rating.
  • Bigger is not necessarily better - you don't want to buy an A/C that is too powerful for the space you are cooling.
    • It will be more expensive than necessary, as well as too cold!
    • An overpowerful A/C will also make a room feel uncomfortably clammy.
  • Choose BTU level according to the size of the room which you plan to cool. The right Btu level -- not too high or too low -- will ensure proper cooling without exorbitant energy bills. ElectricShopping recommends:

Square Footage


100-250 sq. ft.
5000-6000 Btu 
250-400 sq. ft.
6000-8500 Btu 
400-550 sq. ft.8500-11,000 Btu 
550-875 sq. ft.
11,000-15,000 Btu 
875-1200 sq. ft.15,000-19,000 Btu 
1200-1600 sq. ft.
19,000-24,000 Btu 
1600-1800 sq. ft.
24,000-27,000 Btu 
1800-2800 sq. ft
27,000-33,000 Btu 
  • In addition to the above chart, here are some tips on figuring out how many BTUs you need:
    • Find the square footage of the room you are trying to cool and multiply by 35. This will give you the ballpark BTUs you should look for.
    • Shady room? Decrease that number by 10%.
    • Sunny room? Increase that number by 10%.
    • Add 4,000 BTUs if you are putting the A/C in the kitchen.
    • If more than two people will be in the room regularly, add 600 BTUs per person.

Energy Efficiency

  • EER stands for Energy Efficiency Ratio. A higher number indicates a more efficient unit.
  • A higher EER is better (costs less to operate) but units w/ high EER are generally more expensive.
  • An increase in EER by one point can save you roughly 10% on your energy bill. Use this estimate when gauging whether a more expensive model will actually save you money in the long run.
  • Efficiency is correlated with price -- more efficiency requires a greater initial investment. Despite the cost, however, you should buy the most efficient air conditioner you can afford.

Window Size and Installation

  • Before you start shopping for an A/C unit, measure your window two or three times for accuracy.
  • Make sure that the air conditioner you want will fit in your window.
  • Even the lightest air conditioner might weigh more than 20 kilos, and a large unit might be close to 60. Keep this weight in mind when you make plans to install it. (You'll probably want to invite a friend or family member to help you.)
  • Models that come with a slide-in chassis are easier to install - a framework is installed in the window first, and the heavier air conditioning unit slides in easily.
    • This installation takes a bit longer than the conventional air conditioner, however.
  • Through-the-wall air conditioners require you to cut a hole in your wall; this is more difficult and is, of course, a permanent installation.


  • Some models run whisper-quiet, others sound like freight trains.
  • Quieter models may be more expensive, but if you plan to use the air conditioner in your bedroom, you may want to make the investment.


  • A warranty is a good thing to have, especially on something as important as an air conditioner.
  • Most models come with a one-year warranty; sometimes this can be extended to 4- or 5-year plans.
  • If you have someone else install your A/C unit, find out if there is a warranty on the labor as well.

Electrical Outlets

  • Before you buy a unit, check the kind of electrical plug that it uses and make sure you have the appropriate outlet in the area you want to use the A/C.
  • Most experts recommend running the air conditioner on its own circuit to avoid overloading the electrical system.

Other Features

  • Remote Control - particularly useful for air conditioners installed high above the ground.
  • Programmable Timer - set it to turn the AC on half an hour before you come home from work.
  • Air Direction - for best cooling, figure out whether you need the air to blow to the left or to the right - many models blow better in one direction than the other.
  • Temperature Range
  • Temperature Increments
  • Sleep/Energy Saver Setting
  • Slide-out Filter - makes cleaning easier.
  • Fan Speed Setting
  • Dirty Filter Indicator

Major Manufacturers

Related Products

Portable Air Conditioners 


Ceiling Fans 

Standing Fans 

Personal Cooling Systems