The S Series wall-mounted air conditioner features a multistep capacity compressor that uses R-410A. The unit is available in 3 to 5 tons. It has EER ratings up to 11.7 and integrated part-load value efficiency up to 15.2 Btu/watt. Features include ECM indoor blower motor, dual pressure controls, compressor control module, and step-capacity scroll compressor. Ventilation packages range from economizers to an energy recovery ventilator that allows 450 cfm of fresh air.