Buying something bigger than a breadbox? Here's what to consider

Consumer Reports News: August 04, 2010 02:19 PM

When you're shopping for something to cool, clean or dehumidify the air in your home, one boxy appliance looks pretty much like another. Should you opt for the model that takes up the least floor or window space or is bigger always better? Well, that depends. Here's how our experts sized up the situation:

Air conditioners
If you opt for the mother of all air conditioners you may be left with a cold, clammy room. In our tests we found little difference in price between 12,000- and 10,000-Btu models. But buying a model that's too big won't improve cooling. In fact, it will cool the area quickly while not removing enough humidity. And an air conditioner that's too small won't be up to the task of cooling the room. To find one that's just right for your space, use our air-conditioner sizing calculator.

Portable air purifiers
Most room air purifiers weigh from 10 to 20 pounds and stand on the floor or on a table. We've found that a larger unit run at a lower speed is quieter and more effective than a less capable model run at high speed. Manufacturers usually recommend that you run the purifier around the clock in a closed room so noise levels matter.

Dehumidifiers
With a dehumidifier, bigger can be better. A model with a capacity of 60 to 70 pints per day tends to work more quickly and efficiently than one with a capacity of 25 to 40 pints per day. You might also be able to run it on a lower, quieter setting. Consider a small-capacity model only if you're dehumidifying a single room that gets damp infrequently. Go by the claimed capacity on the box, not the dehumidifier's dimensions. Some of the physically largest models in our tests actually had the smallest capacity.

—Gian Trotta