Ceiling fans.
Face the fact: electricity costs are rising. There will probably come a time that you won’t be able to keep up with your current lifestyle such as having centralized air conditioning, heater and so on and so forth. There is in fact a solution to your future problem (that is, if you will experience such in the future): the ceiling fan.
The ceiling fan is very economic compared to your cooling system. A ceiling fan’s range is wide, blowing air to almost three meters in diameter (standard sized). Also, the ceiling fan sucks the air through the sides and blows it to the middle. This can aid the room in maintaining a mildly warm temperature since cold air stays at the bottom (the one being sucked) while hot air rises (the being blown).
Photo taken from http://www.restaurant-services.com