Ceiling fans?

Hi -

I've seen some discussion about re-roofing in order to make one's
house cooler during the summer. However, I haven't seen any
discussion regarding the use of ceiling fans to make one's house
cooler.

Ceiling fans are used in many non-Eichlers for this purpose. Are
there certain aspects about Eichlers that make ceiling fans
impractical (or less effective) than in non-Eichlers?

I can speculate on some possibilities:
1) Electrical wiring is more difficult for anything on a ceiling in an
Eichler verses a non-Eichler.
2) The fans have to extend fairly low, below the ceiling beams (which
don't exist in non-Eichlers). This could be a hazard for tall
people...
3) Perhaps ceiling fans would help more in houses with attics?
But I don't know if any of these are true...

We're looking for ways to keep our house cooler in the summer (we have
a flat grey tar&gravel roof with little insulation). I understand the
cooling benefits of a new roof. However, ceiling fans are definitely
cheaper - if they can do the trick. If they can only cool the house
"a little", is it worth exploring the addition of ceiling fans at the
same time one gets a new roof?