Whenever you move into your new house or shop or office, furnishing the place with affordable ceiling fans is a priority. Besides the aesthetics, the fans also play an important role in controlling the room temperature. Choosing the right fan in accordance with your room space is quite difficult. To our general sense, fans with stronger motors will be able to swirl the fan blades faster, resulting in more amount of air is being circulated. But, faster the fan, noisier it will be and it will consume much more energy.
The smartest design of a ceiling fan is that which circulates a larger amount of air without consuming much energy and performs its task quietly. Fan blade size and the number of fan blades are the two most important factors that control amount of air flow. More the number of blades moving through the air, higher will be the generation of air flow in the room. This law is based on a theory ignoring air drag and air resistance.
So, it is obvious that, there is a trade off in the number of blades to have in a ceiling fan. A lesser number of blades will reduce the amount of drag but may also generate little amount of airflow. But, it is not necessary that fitting more blades to a ceiling fan will generate more airflow because of the larger drag. Increase in drag and air resistance with the increase in the number of blades will increase the weight proportionately and then a more powerful fan motor will be required, which is not at all a smart idea for energy consumption.
In a 2011 study, the airflow generated by an axial fan fitted with blades numbering from two to six fan blades, it is found that 4 blades at an angle of about 45° provide the optimum performance. A sudden increase in the blade pitch would obviously generate more airflow. But it will require a much powerful motor which comes with a greater expense. However, most commercial fans are tilted at just about 16°.
The number of fan blades also depends on your requirement of whether you require a gust or a breeze. A fan with four blades will have not much difference in their work efficiency than a fan with five blades. It will create a certain wind chill effect. If you are looking for a gentle breeze flowing in your room, you might consider a fan with more blades, as much as four.However, it is likely that a five bladed fan will produce less air flow. The five bladed fans have become quite popular in the market because of their good balance in the amount of air flow and the amount of ambient noise produced. The materials and weights of the blades need to be distributed evenly all around the fan to nullify the noise and wobble produced as much as possible.
Despite these variations, the industry is still conquered by fans with two or three blades. This is because a fan with fewer blades is more likely to produce lesser drag of the motor, resulting in the fan to whirl faster. In western countries, they use more than three blades for the ceiling fans but in India, the maximum available is a four blade fan. There are many companies that have a variety of models in compliance with varying number of fan blades. Companies like Atomberg, Crompton Greaves, Havells are a few companies, on which you can put your trust and get best ceiling fans online.