Single-stage and two-stage furnaces have operational differences.
Single-stage furnaces operate at only one output level – full capacity. This may cause temperature fluctuations and higher energy bills because the temperature fluctuates more than with two-stage furnaces.
Two-stage furnaces offer two levels of heat output: a lower setting for mild weather and a higher setting for colder temperatures. 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.