Here’s the logic behind the 3 and 4 blade ceiling fans. You might have noticed, fans come with both 3 and 4 blades depending on the place where they are being used. In India, we usually have them with 3 blades. But the one’s with 4 blades, which are mostly used in the US and colder areas, are not just designed that way to look different. The sole aim of a ceiling fan is to supplement the air conditioner. Which is why the fan, which is slower than the one with 3 blades, serves the purpose of keeping air circulation in the room. The 4 blades move a large mass of air.
However, In India, the fan is mostly used as a stand-alone appliance creating a convective cooling effect. Being lighter, the fan operates at a higher speed and is also energy efficient.