Two-stage operation, or two-stage cooling, means the air conditioner or heat pump has a compressor with two levels of operation: high for hot summer days and low for milder days. Since the low stage is adequate to meet household comfort demands 80% of the time, a two-stage unit runs for longer periods and produces more even temperatures.
Longer cooling and heating cycles also translate to increased system efficiency and greater humidity control. This is important because high moisture levels can increase the potential for mold and other pollutant problems.
By comparison, a single-stage air conditioner or heat pump either runs at full power or cycles off. This can limit efficiency and create temperature swings inside the home.
Copeland Scroll™ UltraTech™ Compressors: The Copeland Scroll UltraTech compressor Is typically used on split and packaged systems under 5 HP. The compressor runs at either 67% or 100% capacity, depending on cooling/heating demand. When partial load is needed, bypass ports inside the compression chamber open which partially unloads the compressor. This allows the compressor to pump only the refrigerant needed to achieve 67% capacity, making this more efficient than hot-gas bypass.
