All air destratifiers are ceiling fans, yet not all ceiling fans are air destratifiers
Air destratifiers are ceiling fans that, using reverse mode to spin in the opposite direction, lower the hot air accumulated at the highest part of the ceiling.
Air de-stratifying principle
Hot air is less dense than cool air, so strata of air with different temperature are formed inside the room - like a cocktail in a glass. Hot air goes up, cool air goes down. There's usually a 2º C difference by linear altitude, which leads to an enormous loss of energy.
Furthermore, this applies to every form of heating, like floor heating, radiators, chimneys.
For example, in rooms of 6 m height with a mezzanine, the temperature difference between the highest and the lowest point of the room can reach 12ºC. In other words, you will have to program your heating to 32º C to be able to feel 20º down, at the floor.
This, of course, causes a massive loss of energy - at the end of the days, you don't need a temperature of 32º C at the ceiling, where there's nobody benefiting from it.
Destratifiers are a solution to this problem, aiming to keep a temperature difference of just 3º over 6 meters, meaning 0.3º to 0,5º of difference for every linear meter.
How does it work?
Blades spin in the opposite direction, sucking up the air. This increases the air speed that moves up, hitting the ceiling and bouncing back along the walls of the room.
While climbing up, air gets cooler, increasing density and making it bounce down even faster, warming up and then repeating the process. Now this cycle has started.
So, what's the difference between a ceiling fan and an air destratifier?
To be considered an air destratifier, a ceiling fan must meet certain requirements:
1) Low power consumption. Because air destratifiers never stop, first speed must consume up to 10 watts.
2) Winter-summer mode accessible from the remote control. Some ceiling fans have a switch on the motor, so in some situations, like high ceilings, it can be almost impossible to reach.
3) They must be compatible with at least 100 cm down rod extensions. Some brands (like KlassFan) are compatible with down rods up to 180 cm. This allows them to get closer to the floor, increasing efficiency both in summer and winter.
Finally, there are also super air destratifiers, these are products designed primarily as destrafiers, not ceiling fans. For example, Modulo by KlassFan, BigCoolEco or Genuino by Casafan.