A Packaged Terminal Air Conditioner (PTAC) can be mounted out of the way for heating and cooling a small space.

A Packaged Terminal Air Conditioner (PTAC) can be mounted out of the way for heating and cooling a small space.


by Janet Akers


When I was in Mexico recently, I rented a small house in the city of Merida, on the Yucatan Peninsula.  Each bedroom had an individual air conditioning unit mounted high on the wall which not only cooled, but heated as well.  They worked quite well.  I recently found out that these units are called Packaged Terminal Air Conditioners, or PTAC.  They are a self-contained unit, requiring no duct work.  You have probably seen similar units in commercial establishments hotels and hospitals, where it’s desirable to have individual temperature control in each room.


The PTAC unit I had was operated by remote control.  With it I could set the unit for hot, cold, or fan only; set the desired temperature; change the fan speed; and set the louvers to oscillate or remain stationary.


PTACs are long and narrow, generally ranging from 36″ – 42″ long and 15″ or 16″ wide.  The unit that I saw was just mounted on the wall, but most are designed to be vented to the outside.  Some also require the condensation to be drained to the outside, though most do not.  Instead, the water extracted from the air is passed over the condenser coil, which causes it to evaporate.


PTACs generally run on electricity.  When set to cooling mode, the compressor pumps refrigerant through the coils.  The cool coils attract heat and humidity, which is removed from the room though the outside venting.  An internal fan sends the cool air into the room.


Some PTACs only cool, the majority also produce heat.  Electric Heat Units have a heating element which is warmed using electricity.  Heat Pump PTACs  reverse the process described for cooling, using the refrigerant to heat the coils.  Most have electric heat backup for colder temperatures.  Both units use the fan to move the heated air into the room.  Electric Heat Units are said to be quieter and last longer than Heat Pump Units.


Apparently, some PTACs use remote sensors to adjust the temperature to increase energy savings.  They can be set for one temperature if they sense someone in the room, another temperature if the room is empty.  Another way the newer models improve energy efficiency, as well as the indoor air quality, is to use a desiccant wheel.


PTACs work better in moderate climates.  Temperatures that are extremely hot or cold will overtax the unit.