arianne's tips: how to buy an air conditioner


Last week, Arianne Cohen told us how to know if you need a new air conditioner. Today she helps us pick out the best model.

I find the air conditioning aisle particularly disorienting: You’re hot, the packages are hard to read, and manufacturers use arcane measurement units to ensure that you’re never quite sure what you’re buying. Pay attention to two numbers, BTUs and Volts, and ignore the rest (except for price, of course).

The most important number on the box is the air conditioner’s BTU rating, which measures the amount of heat the air conditioner can remove in one hour. (BTU = British thermal unit) Help yourself by bringing along the measurements of the room you want to cool. Click through to the next page for an easy-to-use in store test.

Do the following math:

Room length x height x width x 4 = How Many BTUs You Need

You have some wiggle room on that number–if your room heats up from direct sunlight, err in the high direction; if you room is well-insulated or naturally cool, you can err toward fewer BTUs.

The second most important number on the box is the voltage. Most packages say either “120 volts” or “240 volts.” Standard three-prong outlets will support 120 volts, though most homes have a few 240 volt circuits for major appliances. If you’re not sure, buy a 120 volt. If you live in an old home and the outlets are two-prong, then you probably can’t support an air conditioner there. Sorry.

Lastly, you want to purchase an “energy saver” model, preferably one with a timer option. Timers save you ample money in the long run, because you can set them to keep things cool using minimal energy. For example, my air conditioner is set to do the following on a five-hour rotating schedule:

8am: Air condition to 70 degrees
10 am: 15 minutes of dehumidifier (which zaps humidity, which is usually the problem)
12pm: 30 minutes fan
1pm: Air condition to 70 degrees

The temperature rarely passes 72 degrees. And the cost? A cool $.32/day.

For more helpful tips from Arianne, visit her website, or pick up a copy of her book, Help! It’s Broken: A Fix-It Bible For the Repair-Impaired from Amazon.

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