Ceiling Fan Blade Pitch
When purchasing a ceiling fan, a number of factors will need to be looked at. One aspect that is nearly always overlooked is the fan blade pitch. This is the angle of the blade in relation to the fan. The traditional view is that the higher the blade pitch is, the better the fan will be, but there are a number of points that need to be considered to make sure the fan blade pitch is correct.
Avoid any ceiling fans with an angle of less than ten degrees. When the blades rotate, they will not circulate the air as efficiently. It will be like a knife rotating through the air and the noticeable effects will be minimal. The best advice is to ignore fans of this nature, unless they are to be used in a very confined space. The whole point of a ceiling fan is to whip up the air and get it circulating around a room, and these types of fans will not be capable of doing the job. The optimum ceiling fan blade pitch should be around 12 to 14 degrees.
Ignore any fans with a blade pitch higher than twenty degrees. Although these will circulate the air quite nicely, they will attract more resistance and friction. The most common problem with ceiling fans that have a blade pitch of more than twenty degrees is the frequency with which the blades have to be replaced. The bigger the blade pitch, the harder the fan is working. Sooner or later the motor will grind to a halt, as it's forced to work too hard for extended periods of time.
Take care to consider the proportions of the blades. The blade pitch should be similarly proportionate to the motor used to power it. If a small motor is powering an 18-inch blade, it will break down and have to be replaced more frequently. The majority of fans will have a blade pitch of around 14 degrees and will come with an average sized motor. If unsure when buying, ask the dealer about the blade pitch and motor. Never purchase a fan with a small blade pitch and a big motor. The blades will rotate so quickly, they could break and fly off. This heightens the risk of the blades causing serious injury.
The best way to decide whether a ceiling fan has the correct blade pitch is to test it. Dealers will allow you to sample the fans on display and stand beneath them to see the effects. There may be a requirement for a larger motor to be fitted or for the blade pitch to be increased or decreased slightly. A good dealer will take care of these problems if they provide an effective after-sales service as well.