Ceiling Fans Revealed

The history of the ceiling fan goes back to the 1860's. Back then, they were powered by a stream of running water in conjunction with a turbine that enabled a system of belts to turn the blades of fan units. These, by the way, are still in use in the southern states of America. They also consisted of only two blades as opposed to our current, more efficient, four-blade units. In 1882, the first electric fan was invented, which consisted of its own self-contained motor unit and, shortly after this invention, a light kit was adapted onto the ceiling fans to add overhead light.

Ceiling fans consume far less energy than air conditioning units, which is why so many homeowners invest in fans and place them throughout their homes.

Ceiling fans are available in many variations, from standard, inexpensive $50 units to more expensive units that offer features such as variable speed dials, high-quality stator or rotor "stack" motors, and die cast steel construction. Most ceiling fans can reverse the direction in which the blades rotate, blowing air downward (counter clockwise) in summer months to give a cooling effect. Drawing the air upward (blade rotation is directed clockwise) takes the cool air from lower levels in a room and pushes it up toward the ceiling; at the same time, it pushes the warmer air from the ceiling down along the walls and into the room.

Components of a ceiling fan

• Electric motor 
• Blades 
• Blade brackets or holders 
• Mounting mechanism

Motors

Motors vary from oil bath motors, stack motors (oil lubricated,) direct drive motors, skeletal motors, and belt-driven.

The following list demonstrates major ceiling fan styles and the types of motors employed:

• Cast-iron ceiling fans, use heavy-duty oil-bath motors that need to be oiled a couple times per year to maintain lubrication. These fans are sturdily built and, because of their lack of electronic components, last 80 to 100 years or more.
• Stack-motor ceiling fans are powerful and energy efficient. They are designed with a basic stator and squirrel-cage rotor and the fan's blades mount to the central hub known as the flywheel. Flywheels are made of metal or reinforced rubber and are found either flush with the fan's motor housing (hidden) or below the fan's motor housing, known as a dropped flywheel.  There is one disadvantage of this type of fan if the flywheel is made from rubber, and that is that over time it will degrade and you will need to replace the flywheel.
• Direct-drive ceiling fans use a motor that has a stationary inner core with a shell that revolves around it (also known as a spinner motor) and the blades attach to this shell. These are the least expensive motors to produce and the quality is reflected in that fact as these fans are prone to failure and can be very noisy. This type of motor is standard for most of today's fans.  Spinner fans use a direct-drive motor and do not have a decorative cover or motor housing. This type of fan is commonly found in the industrial market. Spinner motor fans (not to be confused with spinners) use a direct-drive spinner motor and do have a decorative cover or motor housing. This type of fan accounts for almost all fans built today. 
• Skeletal motors are a high-quality subset of direct-drive motors, are found on higher-end fans, and have a longer lifespan. Skeletal motors have an open "skeletal" design that allows for better ventilation as opposed to direct-drive motors that have little to no ventilation. The motor is larger and more powerful than direct-drive motors.
• Belt-driven ceiling fans are water powered and work off a system of belts to turn multiple fan units. The "look" is still popular and found in many restaurants and commercial buildings; however, the reproduction of these relics feature an electric motor in lieu of the water powered motor.

Blades

• Blades mount under, on the side, or on top of the motor and are usually made of metal, wood, fiberglass, or plastic. Most fans built for home use come in either four or five blade units while commercial fans usually have three blades. For covered patios or porches that have damp conditions, choose a fan with wicker, bamboo, or rattan blades that are "damp" rated.

Blade brackets

• Metal arms, blade irons, blade brackets, blade holders, or flanges – these are all terms used to describe the brackets that connect the blades to the motor.

Mounting mechanism

There are various ways to secure the fan to the ceiling as the following describes:

• Ball and socket: a metal or plastic hemisphere mounted on the end of the downrod. The hemisphere sits in a ceiling-mounted metal bracket and allows the fan to move freely – ideal for vaulted ceilings.
• J-hook: also known as a claw hook, this system comes in a variety of configurations and secures to a ceiling-mounted metal bolt.
• Low ceiling adapter: this is a kit that you must purchase from the manufacturer and is used on low ceilings where a downrod is impossible to use.
• Close-to-ceiling mount: a ball-and-socket fan designed so that the ceiling cover piece can optionally be screwed directly into the top of the motor housing; then, the entire fan can be secured directly onto the ceiling mounting bracket.    

Other parts

• Motor housing – decorative encasement for the motor.
• Switches – adjusts the speed, changes the direction of the blades, turns the fan on and off, and operates a lamp if present.
• Switch housing – a metal cylinder that is mounted below and in the middle of the fan's motor and is used to conceal and protect various components.
• Downrod – available in many lengths, this is the metal pipe that is used to suspend the fan from the ceiling.
• Blade badges – these decorative pieces hide the screws that are on the underside of the blades (the screws that attach the blades to the blade irons).

Configurations

• If you want to save a lot of money on energy, then look for the Energy Star label. Energy star ceiling fans are not only 50% more efficient, they also have lower price tags as well.
• Huggers, also known as low profile, are ceiling fans that are installed as close to the ceiling as possible. Usually installed in rooms with low ceilings, these fans are never used in rooms with vaulted ceilings.
• Outdoor ceiling fans are specially designed to withstand dampness and should be "damp" rated. These ceiling fans are designed for the porch or covered patio and are not intended to be used anywhere where rain or other water sources can come in contact.
• Other ceiling fans consist of styles such as contemporary, traditional, tropical, rustic, dual motor, carved wood, Victorian, and ceiling fans with uplighting.
• Lighting includes uplights that are installed on top of the fan's motor housing and project light onto the ceiling for ambiance. Downlights are light kits that shine down into the room. Decorative light bulbs are mounted inside the motor housing surrounded by glass panel sections, allowing light to shine through. 

Ceiling fan control options

• Pull-chain – a metal chain or cord is attached to the ceiling fan (2 chains if lamp kit is attached) and operates the on/off function of the fan and or lamp, and the speed of the blades when the chain is pulled. This style is the most common form of operation for household fans.
• Wall-mounted controls – instead of the controls being attached to the fan, these specialized wall-mounted controls are mounted on the wall.
• Digital control – all of the fan's functions are controlled by a computerized wall control. This style of control usually has three to six fan rotation speeds.
• Choke – usually mounted in a standard wall gang box with about four speeds.
• Wireless remote control – some ceiling fans come with this feature; however, anyone can convert their current ceiling fan. Available as an after-market kit, you can install it on your existing fan with relative ease. The remote control transmits infrared signals to the receiver unit installed in the fan, which interprets and acts on the signals.

Comparison factors

A fan's efficacy in generating airflow is measured by the cubic feet of air moved per minute rating (CFM.)  As you start comparing fans, there are many things to pay attention to in order to make the right decision.

• Total surface area. The larger a blade's surface area, the more air it is able to move.
• Length of the fans blades. The longer the blades, the larger amount of the room's air will be impacted. Most blades come in one of three sizes: 36", 42", and 52".
• Blade pitch. The steeper the pitch, the greater the airflow. Increased pitch also means increased drag. Only fans with well-built motors can support steep pitches. Cheaper fans usually have a pitch between 9 and 13 degrees. If you want greater airflow then don't even look at anything with a pitch less than 15 degrees. In fact, for superior airflow you should look at pitches in the 20's.
• Speed of rotation.  This is the speed at which the fan rotates and is measured as revolutions per minute (RPM.) Faster rotation = greater airflow.    
• The space between the fan and the ceiling. If your fan is too close to the ceiling, the airflow will be restricted because the fan won't be able to draw enough air through its blades. A ceiling fan that doesn't use a downrod, such as a hugger, is at a disadvantage. The more space between your fan and your ceiling, the more air-moving potential. In order to meet safety codes your ceiling height would need to be a minimum of 9 feet because blades must be mounted a minimum of seven feet from the floor (though eight or more feet is desired.)
• Blade surface area to air-feed ratio. More blade surface area means greater airflow. If there's too much blade surface area there won't be adequate space between the blades to draw air up through. You'll want to stay away from decorative blades such as palm leafs or systems that have six blades because they do not have enough space between the blades for unrestricted air to be drawn through.
• Number of blades. Less is more when it comes to the number of blades you have on your fan. More blades don't equal more airflow. Four bladed fans will move more air than a five-bladed fan spinning at the same speed.
• Energy efficiency. Airflow generated versus energy input; divide the fans CFM rating by its input wattage (e.g., if the fan moves 6630 CFM on its fastest speed and uses 85 watts to do so, then its energy efficiency is 78.) You can apply this same equation to objectively compare different fans for energy efficiency. 

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