Single-stage and two-stage furnaces have operational differences.
Single-stage furnaces have only one setting, they either operate at 100% or are off. This may cause temperature fluctuations and higher energy bills because the temperature fluctuates more than with two-stage furnaces.
Two-stage furnaces can run at both low and high speed. This allows the furnace to modulate its output based on the actual heating demand, resulting in more consistent temperatures, quieter operation, and improved energy efficiency.Two-stage furnaces provide enhanced home comfort and energy savings compared to single-stage models.