Since air-cooled condensers require little maintenance and offer lower initial cost, they are used in small to medium-sized (up to 20 tonnes of capacity) refrigeration and air conditioning systems. However, the power requirement for a system with an air-cooled condenser is greater than those with a water-cooled and an evaporative condenser due to the fact that the air-cooled condenser requires condensing temperatures of about 15–208C above the temperature of the ambient air.