The answer to 'difference between single stage and two stage furnace' is that a single stage furnace has one heating capacity, while a two stage furnace has two heating capacities. Single stage furnaces operate at full capacity when heating, while two stage furnaces can switch between a lower and higher heating output depending on the heating demand.
Two stage furnaces offer several benefits over single stage models. They are more energy efficient, as they can run at a lower capacity when the heating load is lower, reducing energy consumption. They also provide more consistent temperatures throughout the home, as the lower heating output allows for better airflow and temperature regulation. Two stage furnaces are generally more expensive upfront, but can save homeowners money on utility bills over time.