A Single Stage Gas furnace system is the right HVAC solution for many homeowners, and so, the Trane RunTru 4 Ton 15 SEER 47500 BTU 80% Single Stage Gas Furnace System is suitable for those looking for a gas system with an efficiency of 15 SEER. The individual components of this system are as follows: (1) Trane RunTru 4 Ton 15 SEER A4AC4 Series 48000 BTU Single Stage Air Conditioner Condenser A4AC4048A1000A, (2) Trane A801X Series 100000 BTU 5 Ton 80% AFUE Upflow/Horizontal Single Stage 1/2 HP Gas Furnace A801X080CM5SA and (3) Trane 4 Ton 42000 – 60000 BTU A4MX Four Way Convertible, Upflow, Downflow, Horizontal Left & Right Cased Coil for Split-System Heat Pump & Air Conditioner A4MXC4260AC3HA