Buying Guide to Ceiling Fans

With India being a tropical country, fans are a must have for every home. Fans make you feel comfortable in a room by circulating air. There are a wide variety of fans to choose from, from simple finishes to decorative, four blades to three blades, high air delivery to low noise. Such multiple choices make it difficult to choose the right fan, so let’s makes your choices simpler: Here are a few quick facts that will help you to choose the right fan.

Why ceiling fans are required?

The primary purpose of a ceiling fan is to provide ventilation and improved air circulation to make you feel cooler by virtue of the velocity of air. It is like the comfort of a breeze in an otherwise warm day.

Being a key part of the room decor, ceiling fans can provide a room not only with a comfortable environment but also with appropriate lighting, a decorative touch and enhanced aesthetics appeal.

How fan makes you feel cool?

A ceiling fan cools a room by creating a “wind chill effect”; and not by lowering the room temperature. “Wind chill effect” makes you feel cooler by accelerating the evaporation of perspiration on your skin. It is the feeling you get when you open the window in a moving car.  An air skin velocity of ~1.5 m/sec makes one feel cooler by over 5 0 C.

If you run a ceiling fan in a room whose temperature is 27 degrees, it will create a “wind chill effect” making you feel as if the temperature is 22 degrees. 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.Fans1

How to determine Ceiling Fan Sweep Size?

You should select a fan based on size of the room. Fan sweep size is measured by taking the width straight across from one blade tip to the other blade tip. A fan larger than necessary is fine as long it has space to rotate properly. A fan smaller than needed does not effectively circulate air.

Room Size Fan Sweep
4m* 5m to 4.5m *4.5 m 1400 mm
3.3m*4m to 3.7m *3.7m 1200 mm
2.7m*3.3m to 3m*3m 1050 mm
2.4m *2.7m to 2.4m *2.4 m 900 mm

Important:-To optimize air delivery, your fan should be approximately 3 meters from the ground and 0.3 meters from the roof.

Calculating distance between two fans.

For Larger rooms with more than one fan, the shaft distance between each fan will depend on the sweep of fan.

Sweep of Fan 36″ 42″ 48″ 56″
Centre of difference 1.8 m  2 m 2.5 m 3 m

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 What is a blade pitch in ceiling fan and why is it important?

 Blade pitch is the angle, measured in degrees, between a 180 degree horizontal plane and a ceiling fan’s blade tilt.

PITCH

Why is it important?

 The angle of the blade makes a difference in how much air a fan is able to circulate throughout a room.

This degree of blade pitch will allow your ceiling fan to move the “just right” amount of air – not too much (you don’t need a wind tunnel in your room), nor too little (you do need to feel a nice breeze).

A good way to understand how blade pitch effects air movement is to equate the blades of the fan to the oars of a rowboat. If you have ever tried to row a boat, you know that if you put the oars in the water virtually flat, it takes very little effort to row; but even if you row very fast, the boat moves very slowly. If, on the other hand, you tilt the oars at a steep angle in the water, it becomes very difficult to row the boat, but each stroke makes substantial progress. You will need to be much stronger and in better shape to sustain a higher rate of speed for any period of time in case of the latter.

This principle applies to airflow of ceiling fans as well. Air delivery of a ceiling fan is the result of the aerodynamics of the fan. Its aerodynamic is governed by blade pitch, blade length, and motor characteristics. Hence higher speed /RPM doesn’t necessarily mean higher air delivery. This is a common mistake one does in fan selection by making decisions based on a single parameter like RPM.

That is why leading manufacturer of fans always go through various designing and testing procedure to ensure that blade characteristics and the motor power complement each another.

How important is motor in a ceiling fan?

The motor is the most important component of a ceiling fan. For example, motors with higher power capability can be matched with high pitch aerodynamic blades to deliver high air at lower speed/RPM and hence lower noise. Thus, for a fan to operate efficiently and effectively, the motor’s characteristics must be engineered to match the blades.

Standard ceiling fans have single phase electric motors. These motors are typically of lower efficiency.  With the need to save energy alternate motor technologies are being explored.  The Brushless DC motor is one such technology which is more than twice as efficient.  There are ongoing active developments to make BLDC more cost effective to accelerate its deployment.

Can ceiling fans be used in winter?

It may seem a bit odd to use ceiling fans in winter, but modern age fans are built for year-round use, saving your money on both heating and cooling costs. This can be achieved by changing the direction of the ceiling fan’s rotation (clockwise or anti-clockwise). Depending on the model, the ceiling fan’s direction can be changed through the reverse switch on the fan’s motor or via a remote control.

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Ceiling Fan Direction in Summer: Anti-Clockwise

During summers, run your fan’s blades anti-clockwise to blow air downward and create a cooling breeze so you can set your thermostat at a higher setting and still feel cool while saving money on air conditioning costs.

Ceiling Fan Direction in Winter: Clockwise

During winters, ceiling fans can help heating systems to operate more efficiently. Reverse the direction of the blades and set the fan at a low speed. The fan’s gentle upward draft will force any warm air concentrated near the ceiling to circulate down and around the living space.

The modern age fans are manufactured based on lifestyle needs where in a ceiling fan not only acts as device to make you feel cooler but also adds aesthetic appeal to your room.

11 thoughts on “Buying Guide to Ceiling Fans

  1. As it is given that in Chennai during winter times we do not use ceiling fans because the room temperature is already cool – the logical question is are summer winter fans that effective during summer period when compared with popular regular fans being widely used?

    That is if we do not use air conditioner, when compared with commonly widely used fans – do this switching to summer mode fan do bring any significant difference to room temperature and air delivery?

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    • Generally standard ceiling fans comes with summer operations only, wherein a fan blades moves anti-clockwise to make you feel cooler .and certain modern age fan comes with summer winter operation ,in which there is an add-on feature of winter operation that can be used in winters where the fan blades moves clockwise. This forces any warm air concentrated near the ceiling to circulate down and around the living space, to make you feel warm” .

      So summer winter operation fan has no additional air delivery during summers it functions the same way as standard ceiling fan works during summers but it has an additional benefit where it can be used in winters as
      well , to make you feel warm.

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  2. I have successfully developed an AC by Innovating on Air Coolers, enhancing the current Air Cooler technology. I have ingeniously formulated an organic solvent which I use to process the Cellulose Pads. After this process the properties of the Cellulose are changed so as to deliver Air Condition like chill instead of the High Humidity Cool Air. The lowest temperature that i registered is 19.4 Deg Centigrade when the outside temperature was 46 Deg C. I have decided to name it SabKa AC and want to make it available to the poor people as well (for whom i make in used scrapped Plastic Jerricans & sell it for Rs.3000).
    I would be grateful if you could help me in sourcing cost-effective Exhaust Fans so that I can further reduce the price of my product.
    Thanks
    Sunil Nair
    7698188191
    8138052278 (WhatsApp)
    indiandavinci@gmail.com

    Like

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