Packaged terminal air conditioners and heat pumps (PTACs and PTHPs) are combined heating and cooling assemblies that are typically found in motels and are intended to be mounted through the wall. PTACs may include electric resistance heating or be designed to utilize hot water or steam provided by a boiler for heating. PTHPs can provide heating in addition to cooling by being able to operate the refrigeration cycle in reverse.
The Energy Policy and Conservation Act (EPCA) requires that if the equipment efficiency levels in ASHRAE Standard 90.1 (which is a commercial building energy code) are amended, DOE must either establish amended standards for the products at the levels specified in ASHRAE 90.1 or establish more stringent standards if they would result in significant additional energy savings and are technologically feasible and economically justified. In 2008, DOE finalized new standards for PTACs and PTHPs, which were more stringent than the levels in the 1999 version of ASHRAE 90.1. The standards, which were slightly more stringent for PTHPs than for PTACs (for cooling efficiency), took effect in 2012.
The 2013 version of ASHRAE 90.1 updated the standards for PTACs to align with the DOE cooling efficiency standards for PTHPs. In 2015, DOE adopted the new level in 90.1 for PTACs as the national minimum standard, and the standard took effect in January 2017. The standards for PTACs and PTHPs vary by cooling capacity. The cooling efficiency of PTACs and PTHPs is measured by energy efficiency ratio (EER), which is the cooling capacity (in Btu/hr) divided by the power input (in watts). The heating efficiency of PTHPs is measured by the coefficient of performance (COP), which is the heat delivered (in Btu) divided by the energy input (in Btu).
Technology options for improving the efficiency of PTACs and PTHPs include higher-efficiency compressors and fan motors and increased heat exchanger area.