The Trane XR 80 AFUE Gas Furnace S8X1C100M5PSAA boasts an operational efficiency of 80% wherein a massive 80% percent of the fuel you put into your gas furnace is converted to heat to keep your home warm. Additionally, the gas furnace intends to serve you for several years with its brute tested materials and build quality. Finally, you have the choice to add in Trane CleanEffects™ to give your system the air cleaning boost it needs. Trane CleanEffects™ go into your central air conditioner to further improve its ability to clean the air and give you a more comfortable and healthy environment to live in.