Central air conditioners circulate cool air through a system of supply and return ducts. Supply ducts and registers (i.e., openings in the walls, floors, or ceilings covered by grills) carry cooled air from the air conditioner to the home. This cooled air becomes warmer as it circulates through the home; then it flows back to the central air conditioner through return ducts and registers. To learn more about what to look for when purchasing a central air conditioner system, visit this site.
For even more information on PG&E Energy Efficiency rebates, follow this link. Look under the "Heating and Cooling" section to find out how you can save money by testing and/ or repairing/replacing your homes current HVAC system with a new energy efficient one.