What is the definition of a PTAC thermostat? A PTAC thermostat is a Programmable Thermostat Access Control (PTAC) thermostat, which is a type of programmable thermostat that is designed to control the temperature of heating and cooling systems in residential and commercial buildings. This type of thermostat is typically used in apartments and hotel rooms, and is also known as a wall mounted thermostat. PTAC thermostats are used to control the temperature of air conditioning and heating systems and can be programmed to maintain a specific temperature in a room. With a PTAC thermostat, users can set a specific temperature, and the thermostat will automatically adjust the setting as needed to achieve the desired temperature. PTAC thermostats are also designed to be energy efficient, as they are capable of automatically adjusting temperatures to save energy when the room is unoccupied. They are also highly accurate, as they can maintain the exact desired temperature and