GSHA Services, LTD installed a Dave Lennox Signature SLP99V dual-fuel comfort system at a home on Dupont Court in Elk Grove Village, IL. The system pairs a Lennox Signature SLP99V modulating gas furnace, rated up to 99% AFUE, with a matched Lennox CR33 cased coil and a Lennox Signature variable-capacity heat pump. Our installers removed the old equipment, set and vented the new furnace, brazed and vacuum-tested the refrigerant line set, mounted the heat pump outside on a raised pad clear of snow, installed a new condensate drain and gas connection, wired the disconnect and communicating controls, and commissioned the system with measured gas pressure, temperature rise, static pressure and refrigerant charge. Dual-fuel means the heat pump handles mild weather on cheap electricity and the modulating furnace takes over in deep cold, giving the lowest possible operating cost. GSHA Services is a Lennox and Carrier dealer providing furnace, heat pump and air conditioner installation, HVAC maintenance and repair, plumbing and electrical services in Elk Grove Village, Arlington Heights, Schaumburg, Des Plaines, Mount Prospect, Itasca and throughout Cook County, Illinois.