As its name implies, a two-stage compressor functions in two stages. Some models feature a single compressor with two stages, while others incorporate two separate compressors. In either configuration, the unit primarily operates in the lower stage, running at less than full capacity most of the time. However, during exceptionally hot days, it switches to stage two, operating at full capacity. This dual-stage operation enhances efficiency since the system isn't constantly running at maximum capacity, resulting in energy savings on utility bills.
An alternative to two-stage compressors is variable-speed compressors, which operate at even lower capacities, further optimizing efficiency.