If you have a forced air furnace you could put the furnace on the summer switch so the fan stays on all the time, what this does is circulate the warm air from up to down and visa versa and the fan on continuously uses very minimal electricity. I do this in my suited houses and it makes a big difference. The only complaint I get by some is that when the burners are off it just moves the air so it feels cool by the registers, but the temp in the air isn't cool.
Lisa