Definition
An inverter compressor is a variable-speed compressor whose motor is driven by a frequency inverter, allowing a heat pump to modulate output — typically from about 20 % to 100 % — instead of switching on and off. Matching output to demand improves seasonal efficiency, reduces cycling wear, lowers noise at part load and avoids high starting currents. Nearly all modern air-to-water and pool heat pumps use inverter compressors.