What the best air conditioner has
- Eco-friendly cooling: Look for an air conditioner that uses R-410A as a refrigerant. Not
only is it more environmentally friendly than R-22, but it's cheaper and easier
to find when you need to recharge your unit.
- Energy efficiency: Every window air conditioner has an Energy Efficiency Rating, or EER.
This is a measure of how much electricity it uses -- the higher the EER, the
better. The best air conditioners have at least a 10.0 EER and an Energy Star
- A programmable timer: A built-in timer gives you the power to turn your window air
conditioner on and off even when you aren't around. This cools your room when
you need it while saving you money on your electric bill. A 24-hour timer is
best, which reviewers say is handy to cool off a room before they come home or
to tag team with a central air conditioner at night.
- User-friendly controls: For setting the temperature, digital controls are more precise than a
knob, which typically has only a generic range of warmer to colder. For extra
convenience, a remote control lets you adjust the temperature and fan speed
from across the room. The best remotes also include buttons to set the timer
and toggle through the different air conditioner modes.
- Dehumidifier: Air conditioners pull moisture out of the air as they cool, lowering
the humidity in your room to make it more comfortable. Top air conditioners have
a separate dehumidify mode, which is ideal for humid days without high
temperatures, like in the spring and fall.
- Adjustable airflow: The best window air conditioners have louvers that are adjustable and
effective, cooling specific zones in your room or diverting the air from blowing
directly on you. Experts compare these to the vents in a car: The best designed
louvers aim the air in a general direction, but few are very precise.
- An air filter: Window air conditioners with built-in
filters help freshen the indoor air. Units with an electronic ionizer go one
step further by filtering out odors and smaller impurities. For user-friendly
maintenance, select an air conditioner with a filter that is washable and easy
to remove. An indicator light on the front is extra-convenient, reminding you
that it's time to clean the filter.
- Warranty: A one-year warranty is standard with many air conditioners, but the
best brands also cover the sealed system and compressor for five years.
Know before you go
How much cooling power do you need? The power of an air conditioner is measured in Btu, short for British
thermal units. The higher the Btu, the larger the area it can cool. But bigger
is not automatically better. It's important to match the size of your air
conditioner to the needs of your room: It must be powerful enough to keep your
space cool, but not so large that it shuts off too soon (which leaves too much
moisture in the air).
- Up to 150 square feet: A small air conditioner is best, with 6,000 Btu or less.
- 200 to 300 square feet: Select a medium air conditioner in between 7,000 and 8,000 Btu.
- More than 300 square feet: With a minimum of about 9,000 Btu, a large air conditioner is
necessary to cool bedrooms and living spaces greater than 300 square feet
(which is the equivalent of 15 feet by 20 feet).
- Kitchens: So much heat is produced in a kitchen, that this area needs serious
cooling power. Start by estimating the size of the room, then add 4,000 Btu to calculate
the size of the unit you need.
- Sunrooms and areas with large
windows: An area bathed in excessive sunlight also warms
up more than usual. Figure out the square footage of the room, then add 10 percent
How large is your window? Measure your window opening before you start shopping, as some
extra-wide units won't fit in smaller windows. Most window air conditioners are
designed for windows that slide up and down. Look for a casement window air
conditioner if your windows slide to the side or are hinged.
If a nearby outlet is required. Air conditioners draw a lot of power, so you need an outlet that can
supply the right amount of power and is close enough for the window air
conditioner to plug directly into. If the nearest outlet isn't right below the
window, measure the distance from the unit to the outlet and look for a unit
with a long enough cord. Never use an extension cord with an air conditioner.
Keeping your air conditioner in
good shape. Maintenance is uncomplicated for most
window-mount air conditioners, but a little regular cleaning is important to
keep mold under control (especially in moist climates). Most built-in filters
require washing once a month; replace disposable filters at least once a season
or as the manual recommends. Clean the drip tray thoroughly at the end of
summer to remove mildew, dust and pollen.