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5.4 Self-Contained Air Conditioners and Through-Wall Heat Pumps

This part of the Energy Efficiency Manual explains how to improve the efficiency of self-contained air conditioning units and heat pumps. This part covers window air conditioners, packaged terminal air conditioners (“through the wall” units or “PTAC’s), and air-to-air heat pumps.

Virtually all these cooling units operate on the principle of refrigerant compression. (Absorption cooling is rare and specialized in this size range.) The units include all their components in a single package. Outside air is used for condenser cooling. In the case of heat pumps, outside air is the heat source. The units typically are installed in an opening in the building envelope. They often include heating coils, which are usually electric resistance elements.

The energy conservation measures explained here include the maintenance needed to maintain efficiency, avoiding air leakage or infiltration around the units, more efficient ventilation, replacement with high-efficiency fan motors, and selection of the most efficient units. Efficiency ratings are explained, including EER, SEER, and HSPF.