All of your vents should be open for maxim air circulation throughout your home and to make your system last longer. Closing off individual rooms causes stress on your A/C system and hurts circulation. Aim vents at you the summer and toward the walls in the winter for maxim comfort. Cool air feels good blowing on you but hot air is more comfortable and less drafty if directed up and then down the walls. Ceiling fans have a switch on their body or near the pull chain to reverse direction.