Knowledge Base

When it comes to installing a ceiling fan or replacing an existing one, the number of brands and models offered to you may be quite substantial. To guide your selection for this very common household appliance, we have prepared some information that could help you finding an energy efficient model that can meet your cooling needs.

Things to consider when choosing the size of the ceiling fan
Choosing the right size for a ceiling fan will optimize its performance and efficiency. A large fan in small room or a small fan in a large room will be a total misfit. Therefore the following points should be considered if you want a freshening airflow.

1. The size of the room: the proper ceiling fan size is determined by the room it will be placed in. For best results, the fan should be as close to the center of the room as possible. To get best results it should be at least 8-9 feet (245-275 cm) from the ground level and 1 feet (30 cm) below the ceiling. In a small size room the blade edge should be at least 18 inches (45 cm) away from the wall.
2. The number of blades: as the number of blades goes up, a fan tends to be quieter and circulate less air. Additional blades increase the drag on the ceiling fan’s motor and will slow it down. This is one of the reasons why industrial fans (like wind turbines) usually have only two or three blades: they can go faster, move more air and noise isn’t so much of a concern for them.
3. The size of the blades: when the fan is switched on, the diameter of the visible circle made by the blades sweep is the full size of the blade span.

Source: Lumens.com

Energy Efficient Models
Most people focus on lighting for reducing their electricity consumption even though fans consume a lot more than lights. To give you a perspective, a regular (non BEE1 star rated) ceiling fan consumes 75 Watts as compared to a regular (most inefficient) tubelight that consumes 55 Watts. Moreover a ceiling fan is used during the day as well as night whereas a light is used only during the night. In totality ceiling fans consumes more than twice or thrice the amount of electricity as compare to lights.

This is the reason why it is important to become aware of the power consumption of ceiling fans while buying them. To help you making electricity consumption as one of the deciding factor, Bijli Bachao2 has put up a list of Top Ceiling Fans in India by electricity consumption and performance.

Their ranking, for the standard size 48 inches (1200 mm) sweep fans, is based on data obtained from BEE on air delivery of a ceiling fan (i.e. volume of air and the rate at which it moves) and power consumption (i.e. amount of energy in Watts used to run a fan at high speed). The actual calculation of air delivery / power consumption for various models of ceiling fans ascertains their “Service Value”, which is being used for ranking purpose. The one with the maximum Service Value is given the highest ranking while multiple models with the same value are given the same rank.

Airflow Efficiency: Top Five Ranking of 1200 mm Sweep Fans

Source: Bijli Bachao

As a comparison, Bijli Bachao used an energy meter to measure the power consumption of various fans. You will find below the results of their testing, to which we added a column showing the annual consumption assuming that the fan is working daily for 18 hours.

SuperFan:

BEE 5-Star Rated Fan (a fan similar to the regular ones but with a slightly efficient motor):

Regular Ceiling Fan (2-3 year old in fair condition):

Regular Ceiling Fan (8 year old in bad condition):

¹ BEE or Bureau of Energy Efficiency in India

Useful Links:

Bilji Ba chao

Bureau of Energy Efficiency