[spodek]

Low-tech magazine has an article on how useful ceiling fans are: http://www.lowtechmagazine.com/2014/09/circulating-fans-air-....

They don't pollute nearly as much and work remarkably well. I live in Manhattan, which gets hot and humid in the summer, and basically never turn on my air conditioning even though I pay for my share of the building's central air conditioning. I don't need it and prefer not to cause the pollution.

[NoGravitas]

Here in the South, ceiling fans will let you keep your AC on 80F and still be comfortable. High ceilings help, too, but they're not as common as they used to be.

[saint_fiasco]

High ceilings probably mean keeping your AC on 80F doesn't save as much power as you expect, because it has to cool a larger volume of space.

[logfromblammo]

You're not adding cool, but removing heat. And you're not doing it for the entire volume, but for the 2m layer nearest the floor.

Those high ceilings make it easier to remove heat from that bottom layer, especially with drop ceilings, plenum spaces, insulating spaces, and fans. You are cooling a larger volume of air, but it is not to a uniform 80 degF. The higher layers will be cooled to a lesser extent than the lower layers, so the AC burden is somewhat less overall than if the entire room volume were cooled to a uniformly low temperature.