The difference is not big, 5 blades of electric fan blade single blade area is small, and air role range is small, so the blade vibration is small, the resulting noise and wind cut sound is relatively small sound, blowing out of the wind pressure is also relatively small feel more comfortable. So generally known as the silent fan or comfort fan for more than 5 blades of the fan blade, its cost is higher than the 3 blades of the fan blade, the root of the fan blade and the central axis of the narrow range of connections.
As for the wind smooth, feel comfortable, many fans deliberately designed to change the wind speed for the simulation of natural wind, the safety factor can not be talked about, as for the heat, if you mean to give people cooling, that is, the wind is large, with the power related to the number of leaves has nothing to do.
Expanded information:
Electric fan is short for electric fan, also known as the fan, fan, fan, is a kind of use of the motor to drive the fan blades rotating to achieve the air to accelerate the circulation of household appliances. Accelerated circulation of household appliances, mainly used to cool the summer heat and circulation of air. Widely used in homes, classrooms, offices, stores, hospitals and hotels and other places.
When the electric fan works (assuming that there is no heat transfer between the room and the outside world), the temperature inside the room not only does not decrease, but increases. To analyze the reasons for the increase in temperature: when the fan works, because there is an electric current through the coil of the fan, the wire is resistive, so it will inevitably produce heat to the outside heat, the temperature will naturally rise.
But why do people feel cooler? Because the human body has a lot of sweat on the surface, when the fan works, the indoor air will flow, so it can promote the rapid evaporation of sweat, combined with "evaporation needs to absorb a lot of heat", so people will feel cool.