There is an often cited statistic in the HVAC field that reversing the ceiling fan direction can save 10% on heating bills due to air circulation.
I would imagine that this is somewhat true due to the fan circulating the air.
In theory, reversing the fans direction should flip the intake (blows from high elevation to low elevation) and makes it blow from low elevation to high elevation.
Conceptually this doesn't make sense to me though. In the winter mode, the cold, higher density air appears to be taken through the fan blades and stay on the ceiling only to return down the sides of the walls (kind of like the magnetic field line shape).
If the fan was in summer mode, wouldn't it make more sense to have the hot air pass down directly through the blades (where the warm air would be more concentrated) and warm the center of the room instead of the edges? Or is this for the entire house and not the benefit of any one person in the room?
Is there even any scientific evidence behind some of these claims, or is it mainly a marketing point?