The Infinity® 98 gas furnace line with Greenspeed intelligence operates at a gentle, low capacity up to 90 percent of the time. When combined with an Infinity control, the modulating gas valve in the Infinity 98 furnace can adjust heating output up and down through multiple stages in 1 percent increments from 40 up to 100 percent of capacity to more accurately match comfort needs while increasing the energy efficiency of the furnace. The expansion of the Infinity 98 gas furnace line includes additional sizes and the most energy efficient furnace (Model 59MN7A060V21-20) in the industry, with an AFUE of 98.5 percent, claims the company. The furnace’s quiet operation is made possible by technology that distributes heated air at the lowest possible setting for the majority of the heating season. In low-fire mode, where the furnace operates most often, it is very quiet, less than the sound of a running refrigerator, the company said.