Mostly the whole system of the central air conditioning units are located outdoors such as an outhouse or a rooftop. The British thermal unit (Btu) rating and EER (Energy efficiency ratio) are the two important things that determine the efficiency of a central air conditioner. Btu measures the amount of heat the air conditioner can take away from the room and the EER rating gives you an idea about the energy efficiency of the unit. A manual or programmable thermostat controls the temperature of air given out by the unit.

The filters of the unit clean the air and it can be easily cleaned or replaced. Central air conditioning units with a fan are more effective than the other ones. A common temperature will be maintained for all the rooms and some types come with controls for individual rooms. There are advantages in using a central unit as it is located outside the house and so the noise of the unit will not disturb the calm of the home. A stylish filtering system cleans the circulating air in the building through a variety of return-air ducts and room air is continually drawn in and filtered. Through this procedure, even microscopic pollutants and dust particles are filtered from the circulating air.