Get The Essential Fan Facts

Essential Fan Facts – What You Should Know Before Buying Your Ceiling Fan

General Considerations

While many ceiling fans may look similar to or even exactly the same as a quality brand such as Hunter do remember that all ceiling fans are not created equal. Educating yourself before you buy will save you disappointment and wasted money.  Here are some important things to consider before making your purchase:

– How much air is actually being circulated?
– How efficiently will the fan move air?
– How quiet or noisy is the fan?
– Will the fan wobble?
– How long will the fan last?
– How durable is the finish?
– Will the manufacturer stand behind the warranty?

How Is Airflow Measured?

Air movement or flowrate is measured in metres cubed per hour, m3/h or in old units cubic feet per minute, cfm.  To convert cfm to m3/h just mulitply by 1.7.  A ceiling fan should move a minimum of 7,000 m3/h to be doing very much.  A typical desk fan will move 800-1200 m3/hr unless it is a Dyson, in which case it will be a fraction of this since they are particularly weak.  An decent flowrate is 11,000 m3/h and some of the more powerful ones with 152cm/60″ blades will move up to 18,000 m3/hr.  Just how much you need  will depend on your room size and how hot it is likely to get in the summer.

Why Do Some Fans Move Little Air?

A ceiling fan that looks nice but moves little air is of little comfort or use to anyone. One of the keys to proper air movement is blade pitch. The greater the pitch, the angle of the blade, the greater the air movement.  However this can result in more “propeller” noise and more turbulent airflow.  Turbulent airflow is far less comfortable than laminar flow and is also more inefficient therefore using more power.  To avoid these disadvantages the blade pitch needs ideally some twisting in it and to also be tuned to the motor. Some cheaper manufacturers skimp on materials and don’t use large enough or powerful enough motors to drive a proper blade pitch. So to reduce the stress on undersized or under-powered motors they compromise on blade pitch thus sacrificing proper air movement. Many fans also use extra thin blades to reduce cost. The reduced blade surface area also means reduced air movement as it is the blade surface that is forcing the air forward.

Why Are Some Fans Less Efficient?

The amount of energy a fan consumes plus the volume of air the fan moves determines the fan’s overall efficiency. Small, low wattage motors may use little energy, but they also move very little air, resulting in very inefficient fans.  Ceiling fans are far more efficient than desk fans simply due to the larger blades sizes which produce decent laminar (smooth) airflow requiring a fraction of the power. That is not the end of the story though as efficiencies do vary widely between brands depending on the quality of the components used and the design.  In general DC powered fans are about 70% more efficient that an equivalent AC powered one.  Note that a DC powered fan still is connected to the regular AC mains but it converts the power first into DC internally before applying it to the motor.  This saving in power also means less heat is produced -and energy lost – by the actual operation of the motor.

Why Are Some Fans Noisy?

An electrical humming created when a ceiling fan is running is usually the result of poor engineering design and a lack of precision manufacturing. Some manufacturers use generic cheap ball bearings to reduce cost, even though these are a common source of operating noise. A lack of proper dampening between metal parts can also create and intensify noise, as can the use of extra thin sheet metal motor and mounting system parts. Finally cheap capacitors, which are what are used to control the speed and startup of a fan, are very likely to start to break down after 18 months creating annoying hums and limiting the fan speed before going on to finally fail.

Why Do Many Fans Wobble?

Another source of noise can be wobble. Many factors can produce fan wobble. Substandard blade materials and improper blade sealing can produce blades that absorb moisture and warp—a prime source of wobble. Blades that are not matched in carefully weighed and balanced sets can also wobble. Inconsistent blade mounting brackets can create varying degrees of pitch (blade angle), throwing a fan into an unbalanced wobble. And poorly manufactured motors have rotors that can easily get out of balance, generating wobble from the very heart of the fan. Inexpensive mounting systems with pin fasteners are another culprit.  Finally any wobbles should be eliminated at the installation stage by using a balancing kit.  The kit consists of small sticky lead weights that can be placed on the topside of the blades to balance up the blades.  They should only be used as a last resort as any decent brand should not  need this unless the blades are real wood in which case some movement and moisture changes since manufacture can affect them.

What Are The Main Reasons For Failure?

Some of the more common reasons a ceiling fan can fail are:

  • The motor size and blade pitch are not specified and matched correctly.
  • Improperly installed on/off pull chains can become faulty and be pulled out of the housing.
  • Inadequate quality, testing, manufacturing and inspection procedures send poor quality fans to market. Defective motor windings can lead to electrical shorts in the motor.
  • Low quality fan bearings may be “shielded” on one side only, allowing dust to enter and cause premature failure.  Bearings are not sealed for life.
  • Inexpensive materials, poor engineering, and substandard manufacturing processes are used to create “bargain” fans.

Are All Brass Finishes The Same?

Wnen new all brass finishes look great and the quality differences will not show. After a year or so differences start to emerge.  Tarnish and dark spots or pitting begins to appear especially if located in a cold damp environment such as a conservatory. You may even notice the brass on the fan is a different color than the light kit you just added.  As time goes on the pitting may get bigger and turn into wholesale peeling as the cheap metallic finish simply corrodes and falls off.

Quality brass and other metallic finishes include a series of grinding and buffing steps between multiple plating processes. To help determine the quality of a plated finish, look at the surface closely for scratches or unevenness of finish. Does the surface spot easily? If so, avoid the fan. Can you feel a smooth protective coating? That’s a sign of the kind of quality you’ll find in fans such as Hunter.

What Is The Min Height I Need?

Safety standards state that the min height from the floor to the bottom of the fan blades must be 2.3m or 7ft 6″.

How Much Cooling Do I Get?

The air moved by the fan creates a wind chill effect on the skin that makes you feel more comfortable in a warm room. The more air that is moved, ie the higher the flowrate then the cooler you will feel up to a maximum of 3-4 ° C.  Once that is achieved any additional flowrate has no effect and so is wasted but up to this point here is a direct relationship between air movement and comfort – the more air moved, the greater the wind chill effect.  Hunter fans generally move more air than competitive models because of custom-engineered motors and blades pitched at the maximum possible angle.  If there is a source of cool air either from an outside window or from an air-conditioner then the fan will suck in the cool air and achieve a much higher degree of cooling.  When used in conjunction with an air conditioner, a ceiling fan can lower energy costs, because you can set the thermostat of your air conditioner at a higher temperature.

Do More Blades Cool More?

The main difference between a 4-blade and 5-blade fan is aesthetics. For a given motor power there is a direct relationship to the air moved and adding more or less blades will make little overall difference.  Adding more blades has more blade surface to push the air but increases the drag which slows the blades more and so will run slower giving the same overall air movement.  The additional drag might increase the noise slightly although since it is moving slower this will counteract it.    Depending on the characteristics of the motor you might find one effect overcomes the other and so the reduction in speed due to the increased drag might overall move less air.  In general though it won’t which is why a fan with two or even one blade can still move as much air albeit they are likely to be spinning faster and therefore be noisier.

All the fans we sell, whether 3, 4 or 5 blades, are designed for optimal air delivery.  Other alternatives to having less blades and making the fan run faster is to have longer blades or have a greater angle.  Both of these parameters increase the effective blade area in contact with the air leading to greater movement.

What Size Fan Should I Purchase?

You need to choose the right size fan for a room to get optimum comfort and energy savings. If the fan is too small for the room, it will not move enough air to make you feel comfortable. If the fan is too big, it could move too much air making it windy instead of breezy although you can always just turn the speed down a notch. If it is too small you cannot turn it up so it is best to err on the side of caution.  Hunter recommends the following sizes:

Room Area                  Blade Span

100 ft2                          30-48″

400 ft2                          50-54″

>400 ft2                        56″

Can A Fan Be Used In The Winter?

A ceiling fan can help lower energy consumption in the winter by up to 20%. The temperature of the air in a heated room varies in layers; the air near the ceiling is warmer than the air near the floor, because warm air rises. A ceiling fan can help push the warmer air that is trapped near the ceiling back down into the room, thus destratifying the layers of warm air. As a result, the warm air is circulated where it is needed, and the heating system does not overwork to warm the room. To properly destratify a warmed room, the ceiling fan should be run in a clockwise direction instead of the usual anti-clockwise direction. This pushes the air up against the ceilings and down the walls, to gently recirculate the warm air without creating any cooling wind chill effect.

How much electricity will a fan draw?

On average, a ceiling fan run on high speed will consume less power than a 60-watt light bulb.  The new DC low energy fans however are far more efficient and move up to 70% more air per watt of power.  They use typically 35 watts for a fan that moves 11,000 m3/h of air and an incredible 3 watts on the lowest speed which means that they can be left on all the time without generating any great cost.

How Much Can I Save In Running Costs?

A ceiling fan can save up to 95% on cooling costs over air-conditioning for a new install and 47% on an existing system.  It can also save up to 20% on heating costs when operating in reverse in the winter. Savings will vary depending on local climate conditions and energy costs.

How Easy Is It To Install A Ceiling Fan?

Installing a ceiling fan is suitable for a competent DIY person. You will need to be able to: 1) locate a 2″ x 4″ or other suitable support in the ceiling, 2) drill holes and install wood screws, 3) identify and connect electrical wires and 4) lift the fan (most weigh less than 35 pounds/15 kg but can get heavy if holding for a while although most do have hanging hooks to assist).

What Is Covered By The Warranty?

Most fan warranties are limited warranties that cover the motor parts for the stated life of the warranty; that is, a 20-year warranty will cover the motor parts for 20 years. Labour for the motor is generally covered for 1-year, as are parts and labor for all other components of the fan. All Hunter fans are backed by a “limited lifetime motor warranty.” Most importantly, Hunter is the only fan company with over 125 years of experience behind its warranties.  See the warranty section above for more information.

Can I Use A Remote Control?

Most ceiling fans can be adjusted with an remote control sold separately from the fan. In fact, remote controls can really enhance the performance and operating flexibility of ceiling fans since many include one-touch multiple speed settings, instant fan “off” operation, and full range light dimming — all possible from the comfort of your favorite chair or bedside table. Ceiling fan and light remote controls can easily be installed either with the fan during new installations or on fans which have been previously installed and in use for some time. The installation is an easy for the competent DIY person and does not require any professional wiring. Remote control kits include a handheld transmitter for sending commands to the fan and a receiver which either conceals inside the fan canopy or mounts just beneath the ceiling. Remote controls can operate the fan or light reliably up to 40 feet away from the fan.

Can I Mount My Fan On An Angled Or Vaulted Ceiling?

Yes, ceiling fans can be installed on angled or vaulted ceilings by using a fan canopy (the “cap” visible closest to the ceiling which covers the electrical box) which has been designed to accommodate sloped ceilings. Many quality fans will include this type of adjustable canopy but if not included with the fan at original purchase, accessory canopy adapters are sold separately.

Why Should I Use A Droprod?

For the optimum performance, comfort and the greatest energy savings a ceiling fan should be installed 8 to 9 feet above the floor. Extension drop or down rods are used to properly position fans from ceiling heights greater than 8 feet.  A general formula for calculating downrod length is: ceiling height in feet minus 9′ = downrod length.  For example, a 12 foot ceiling would need a 3 foot down rod to position the fan at 8 feet.  Note that one foot must be allowed for the distance from the top of the fan motor to the switch housing bottom.

Will My Fan Wobble If I Use A Downrod?

Using long-length downrods for fan installations actually help stabilize fans and reduce the potential for wobble. Think of a grandfather clock pendulum and its slow, heavy swing versus a smaller clock pendulum with a fast, unsteady swing. Weight and length combine to create stability, reducing wobble, whether it is in a ceiling fan or a clock pendulum.  Regardless of this if the fan is balanced correctly it will not wobble.

Why Does My Fan Hum When I Installed A Variable Speed Control?

Most ceiling fans are operated by capacitors. These create distinct speed “steps” like high, medium, and low. Capacitors should control the fan speed in a way that does not produce a hum unless they are cheap or inferior quality. Variable fan speed controls, which create a speed control range from low to high, are operated by solid state electronics. Variable controls can create a hum because they control the fan’s speed in a different manner and therefore should be avoided.

Can I Control A Fan And Light Kit From The Same Wall Switch? 

The answer here depends on how your wall switch is currently wired. If you have a single wall switch with three wires, one neutral, one live and earth then the answer is “no”.   The answer is “yes” if you have an extra wire termed the “switched live” in the single wall switch which takes the power to the light when it is needed. This is commonly referred to as 4-core wiring and is not used by default but can be readily fitted by an electrician.  The exact cost will depend on the location of the room.