The ideal location for the thermostat is in the room where you spend the most time. Dirty filters cause your AC unit to work harder when circulating air and leads to both higher energy bills and a shortened life span. Some types of filters can be rinsed out and reused. Check your air ducts for leaks and obstructions. Most air leaks in central AC units occur in the return air plenum.
Plenums are the large ducts above or below the air handler.
When these leaks occur, warm air is pulled into the system, and the cooled air is heated up. If your central AC system is unable to cool your home satisfactorily, leaky ducts may be the cause. Ducts can be sealed and insulated and thus improve your AC systems efficiency. Use the correct refrigerant charge. This can greatly affect your air conditioner s efficiency.