"Ceiling fans are a good deal and very efficient," says Kate Lewis, marketing manager for the Environmental Protection Agency's Energy Star program. Since heat rises, they help you feel cool by creating a downdraft that stirs the cooler air along the floor. (In winter you can make a room more comfortable by keeping your fan on low with the blades running in the reverse direction to force warmer air near the ceiling down into the room.)
Best for: Large rooms, thanks to blades that measure from 24 to 60 inches (the longer they are, the more air they can push around). They're also helpful where you don't want to sacrifice table or counter space to a desk fan. You'll cool a 12-by-12-foot room most efficiently with 42-inch blades; for a 20-by-20 room, you'll need 52-inch ones (go to energystar.gov for more size guidelines).
Placement: Mount the fan in the center of the room (ideally, at least 18 inches from any wall), with the blades 10 to 12 inches below the ceiling (but no less than seven feet from the floor).
Features to look for: Proper blade length, remote control (especially helpful for users who have difficulty reaching a short chain), Energy Star label (guarantees efficiency).
2 of 4Andrew McCaul
Pedestal fans can adjust, allowing the breeze to hit you where you need it most. Get one that oscillates on its base and you’ll blow air all over the room.
Best for: Medium-size rooms, since pedestal fans can’t cover as much area as ceiling fans do. Their height and oscillation let pedestal fans cool a number of people at once.
Placement: Station your pedestal fan in a spot where furniture won’t block the airflow, and adjust its height as necessary to clear coffee tables and the sides of sofas. To air out a stuffy room, place the fan in a doorway or in front of a window to allow fresh air to flow in, suggests Ace’s Helpful Hardware Man, Lou Manfredini.
Features to look for: Adjustable height, adjustable speeds, 90-degree oscillation, sturdy base (before buying a fan, try to oscillate it on the highest speed to see if it wobbles or rattles), removable metal grille (for durability and easy cleaning).
3 of 4Andrew McCaul
The most effective fans for small spaces don't mimic a wind tunnel―you want a little comfort in your cubicle, not a mini cyclone of paper. To get good circulation from a desk fan, try an air circulator. Unlike fans that blow a stream of air in one direction or oscillate to move air back and forth, an air circulator has curved vents that create swirling currents.
Best for: Smaller rooms. They're also effective and energy-efficient spot coolers―for example, when you're reading in your favorite chair in a big living room.
Placement: A desk fan cools you best when set on a table or a countertop no more than a couple of feet away so the air blows directly on your skin. To relieve stuffiness in a room, place the fan on a flat surface at least four feet high and angle it so it blows up the wall to move stale air, suggests Benjamin Bodie, field-operations manager at the Patterson Fan Company, near Columbia, South Carolina.
Features to look for: Tilt adjustment, adjustable speeds, removable grille, weighted base (to prevent accidental tipping).
A fresh breeze is one of the best things about summer, but sometimes you don’t want to have to go outside to get it. Capture it instead with a fan that sits in your window and sucks air into the house rather than just circulating what’s already in there.
Best for: Rooms that get hot quickly (such as those with large windows that receive direct sunlight) or where floor or counter space is tight. They’re also great for use in the morning and the evening, when the air outside is cooler than the air inside. At night, window fans can clear out the stale air that makes you toss and turn.
Placement: Usually they’re held in place by the lowered sash of your window (no screws or drilling); they should come with extension panels so they’ll fit into most openings. They can be mounted horizontally or vertically, depending on the direction in which your window opens.
Features to look for: Twin fans with three airflow settings (air intake, exhaust, and exchange), extension panels, horizontal- and vertical-mount capability, remote control.