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 uneven heating and fluctuating bills because the furnace is either running at its maximum setting or completely off..
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.