Air conditioning technicians install and perform maintenance on cooling and air conditioning systems. In this role, you determine what size unit is required for the home or office, find the best location for the air conditioning unit, install the unit, and test it to make sure it runs properly and does not disrupt any other system in the building. When the system stops working or has other issues, you examine the unit, make adjustments or repairs, and troubleshoot other problems that may arise. Some technicians focus exclusively on AC units, especially in companies that maintain a lot of them, but other technicians also concentrate on heating and ventilating systems. In these cases, the job is often called an HVAC technician instead of an air conditioning technician.