If you can do something about it, there is no need to worry about it; if you cannot do anything, then there is also no need to worry.
Given that we've changed the layout of the house to catch the prevailing breezes, we were planning on doing without air conditioning alltogether. We figure that with this greatly improved cross-ventilation and the addition of a cool roof, reflective foil and some bulk insulation, ceiling fans in most rooms should be adequate to keep us comfortable.
So off I go researching ceiling fans ... and it's rather insane what I discovered:
Too few fan manuafacturers and retailers publish this kind of critical information. It seems that all too often purchasing decisions are made based on how a fan looks rather than how well it is likely to work and what can be done to maximize its efficiency and thereby reduce the need for air conditioning.
I think that we need something similar to the energy star rating for all such appliances with minimum standards set that would eradicate inefficient and substandard models from the market. More consumer information and education would also be helpful.
FYI, we decided to go with the Hunter Pacific Typhoon ceiling fans with CFLs and extension down rods where applicable. This model has a 22 degree blade pitch and got a good writeup in Choice magazine.