FAQs about Packaged Terminal Air Conditioners (PTAC)

What is a PTAC?

PTAC is short for Packaged Terminal Air Conditioner. The name is somewhat misleading, though, because PTACs generally provide heating as well as air conditioning. It’s a self-contained, ductless, wall-mounted unit that can cool or heat a room more efficiently than central heating or air conditioning.


How does a PTAC work?

A PTAC uses electricity to pump a refrigerant through a compressor. The refrigerant cools the coils in the unit, which in turn cools the air that passes over them. Cool air is blown into the room by the PTAC’s fan while heat and humidity is vented outdoors. The heating function works the opposite way, pulling in cool air that is warmed up and blown into the room as it passes overheated coils.


Where should PTACs be installed?

Since PTACs are designed to cool and heat relatively small spaces, it’s best to install them in buildings that have a large number of small separate rooms, like hotels, motels and assisted living facilities.


Why are PTACs more efficient?

Buildings with a large number of rooms often don’t have all those rooms occupied at the same time, or may have them occupied by people with different comfort levels. Having individual air conditioning and heating units allows the person in each room to control their own comfort level, and allows the building manager to set back the units in rooms that are unoccupied.


How can building management control the temperature in unoccupied rooms?

Buildings can maximize the energy efficiency of PTACs by installing an energy management system, or EMS, to automatically control the units. The most basic type of EMS is an occupancy sensor, which can detect people entering or leaving a room and adjust the PTAC’s temperature settings accordingly. More sophisticated EMS systems can use web-based monitoring technology to control the settings of dozens of PTAC units within a building.


Despite their name, can PTACs provide heat as well as air conditioning?

Yes. PTACs can control comfort year-round by providing heating as well as cooling. PTACs are generally equipped with either a heat pump or electric heating system. Heat pumps cost less to run than electric heat, but the climate your building is in will determine which type of heating system is best. Heat pumps tend to operate better in milder conditions while more powerful electric heat is the better option for buildings in colder weather areas.


How do I know which PTAC is the right size for my needs?

Getting the right sized PTAC – in terms of its British Thermal Unit, or BTU, rating – is more complicated than simply basing the size of the unit on the square footage of the room. Factors like your building’s age, condition and insulation must also be taken into account, along with the temperature extremes in the area where your building is located.


Why is sizing so important?

If your unit isn’t properly sized, you could end up with higher electric bills or maintenance expenses. A unit that’s too small in terms of BTUs will have to run more often, using more electricity and putting a strain on the equipment. On the other hand, an oversized unit will run less efficiently because it will create greater temperature swings that will cause it to cycle on and off more often than it should.


Are PTACs eligible for energy efficiency incentives?

You’ll need to check the eligibility requirements of the utility or government energy efficiency incentive programs in your area. In some cases, eligibility may depend on the energy efficiency rating of the PTAC units or the addition of an EMS.