Single Vs. Two-Stage Furnaces

If you’re planning to replace your older furnace, there are some advancements in home heating equipment that are worth exploring, like two stage furnaces. If you’ve always had a single-stage furnace, it’s good to learn how a two-stage model functions in comparison and what benefits the newer technology offers.

Comparing How Single- and Two-Stage Furnaces Function

The major difference between single-stage and two-stage furnaces is the gas valve:

• Single-stage furnaces have a fixed, single-position gas valve that offers only one level of heat output. This kind of furnace always operates at 100 percent capacity.
• Two-stage models have dual-position gas valves with both high and low settings. The low setting utilizes about 60 to 65 percent of the unit’s total output, while the high setting utilizes its full capacity. A two-stage furnace can automatically switch between the two settings, so it can adjust its output and fuel consumption on milder days.

Two-Stage Furnace Benefits

The opportunity to curb your fuel consumption and heating costs during milder weather is a big benefit of owning a two-stage furnace. Two-stage technology offers other advantages too:

• Better comfort control. With your single-stage furnace, you get a big blast of warm air then a cooler period with every on-off cycle. Two-stage units run on low more often, but for longer cycles, so there are fewer issues with temperature fluctuations and hot or cold spots.
• Less noisy operation. With the prolonged cycles and low-speed operation of a two-stage furnace, you’ll hear fewer irritating “bangs” as it cycles on, and less noise when it’s running compared to your current single-stage unit.
• Longer service life. Since a two-stage model runs on low much of the time, there’s less strain and wear put on the various heating system components. If you keep it properly maintained, you can expect it to last longer than a single-stage model.