6. Close Unnecessary Rooms and Vents
If you have a room that tends to run warm or is not used regularly, you can save money and make the rest of your house cooler by closing the vents in that room.
It is also best to close the door and leave it that way unless you absolutely have to enter the room for something. You can make this even more energy efficient by putting something in place to block the gap at the bottom of the door.
Always remember that your A/C can only produce so much cool air, so you want to make sure that it is diverted to the most important areas.
Photo by Marcus Vinicius