I recently learned that ceiling fans are complicated. This surprised me. I had assumed that a fan was a fan -- if you wanted more fanning, you might get a bigger fan, or a fan with a faster motor, but that was pretty much as far as my thought process went. Little did I know...

Buying The Right Fan:
There are all kinds of things to consider when buying a fan, but fortunately the fan industry has simplified matters for us common folk. When shopping for a fan, you will be looking at two main issues; fan size, and motor quality.

Fan Size:
The size of fan that you want is primarily dependent on the size of room you want to... um... fan. According to the American Lighting Association:

 If your room is:   --   Then you want a:   
 Up to 75 square feet:   29 to 36 inch fan. 
 76 to 144 square feet:  36 to 42 inch fan. 
 144 to 225 square feet: 44 inch fan. 
 225 to 400 square feet: 50 to 54 inch fan. 
These sizes in these rooms will provide maximum air flow. Fans should also be mounted 8 to 9 feet above the floor. While the distance between the fan blades and the ceiling isn't as important, the flush mounts (used in rooms with low ceilings) are not as effective in creating air flow as are standard mounts.

Motor Quality:
Fans are usually graded into three qualities, based on motor strength and quality. There are many types of fans that do not fit into these categories, but we can disregard these as either 'industrial grade' or 'crap'. The big fancy fans are not particularly useful in a private residence, and the little cheap ones (sometimes called 'promotional grade') are pretty much worthless. Here's what most of us will be looking at:

Performance Grade: The highest grade of domestic ceiling fan, they have durable, powerful motors. The more powerful motor allows for a higher pitch to the fan blades, giving much more air flow. They can move a lot of air, and they can be run constantly without problems (although even high performance fans should be given a rest every few days). Prices run from a couple hundred dollars up into the thousands.

Medium Grade: A good fan, but built with price in mind. These go for around a hundred dollars each. Aside from the price, the major difference is that these fans are not designed to run constantly, and should be run for only up to 12 hours a day. They are also at their best in rooms with a 12 foot ceiling or less.

Moderate or Economy Grade: As the name says, these are the economy model. These fans should be run for less than 8 hours a day, and work best in a room with 8 foot or lower ceilings. Economy grade fans move noticeably less air than do higher grades.

Other considerations:

Weight: Although it might seem counter-intuitive, heavier fans are often better. A motor casing made from heavy materials will reduce vibrations, thus increasing performance and efficiency.

'Wet' or 'Damp' Rating: If you're buying a fan for a humid area (patio, porch, or bathroom, for example), you should get one that has a UL 'wet' rating. These fans have sealed motors, rust-resistant materials, and blades that won't warp when they get wet.

Using your fan: As kmcardle says, fans can be used effectively in the winter as well as in the summer. But allow me to make the clockwise/counterclockwise relationship clear: counter-clockwise rotation is for summer usage, cooling by wind chill, while clockwise is for winter use, recirculating the warm air without producing a draft.


A note from Transitional Man:

Since people pay me to install ceiling fans, here are a couple points.

  1. Fans are heavy and vibrate. Thus the ceiling box has to be reinforced, and braced much more strongly than your basic light fixture.
  2. The best fans are quieter, but can cost 10x the cheap fans. A top of the line Casablanca might go for over $400 and the motor must be lubed by the installer.
  3. Most are wired for a light to be hung below the fan, with a supplied or optional light kit. If you have two switch legs they can be shut off from a wall switch (my preferred method), if not you're stuck with pull chains. The remotes are nice, but expensive.