The average base price for an 80,000-BTU Trane gas furnace with 3-ton blower ranges from $1,200 to $2,000, depending on the model and efficiency rating, as of 2015. Trane does not provide pricing or MSRP directly to consumers, since it only allows certified dealers to sell and install its furnaces.
Trane gas furnace models include an 80-percent-efficient standard furnace, 80-percent efficient furnace with variable speed blower, a 90-percent-efficient furnace and a 95-percent efficient model. The furnace price increases as the efficiency level increases, but more efficient units lower monthly gas costs. The base price increases if the furnace's BTU capacity is increased. In addition to the furnace price, average installation costs range from $1,200 to $1,500.