The company's line of residential gas/electric packs now includes a 13-SEER unit. The R4GD has two-stage heating. The variable-speed blower maximizes air conditioner efficiencies and optimizes humidity removal and filtration capabilities, the company states. The units are easy to handle and transport, and they provide quick access to the refrigerant system without disrupting operation, the manufacturer says. They can be installed on a roof or a slab. The galvanized steel cabinet is designed to protect coils from damage caused by extreme weather or flying debris.