What Is Two-Stage Heating?

If you’ve been shopping around for a new furnace, you’ve probably run across the term “two-stage heating.” This comfort-enhancing feature is worth getting familiar with because it’s especially useful in west central Florida’s mild climate.

Simply put, a furnace with two-stage heating has two levels of heat output:

  • Low, which provides limited heat output for moderately chilly weather. This is usually around 50 to 75 percent of the furnace’s full capacity.
  • High, or full capacity heat output sufficient for the winter’s coldest days

How Two-Stage Furnaces Work

A conventional single-stage furnace uses a fixed-output gas valve and a blower motor that runs at just one speed. Not surprisingly, this allows for only one level of heat output. That level is great for cold days, but usually too high for mild weather.

When the weather is mildly chilly, the furnace will cycle on and off frequently in an attempt to maintain a low heat output. This causes temperature swings and unnecessary wear on the components.

A furnace with two-stage heating contains a two-stage gas valve that has a low-fire and a high-fire setting. The multi-speed blower motor in the furnace can run at a low and high speed. Some furnace models have variable-speed blower motors that can run at a wide range of speeds.

Typically, the furnace will kick on at the low setting. If the temperature the thermostat is set for isn’t reached within a few minutes, the furnace will kick into high.

Two-Stage Heating Means Greater Comfort

Two-stage operation doesn’t improve the furnace’s energy efficiency. Instead, it helps the furnace better meet your heating needs.

Around 80 percent of the time, the low setting will provide enough warmth to keep you comfortable. That means your furnace will run at a lower setting for longer periods. You’ll see benefits such as:

  • More consistent and even heating throughout your home
  • Quieter operation since the fan motor runs at a lower speed
  • Greater air filtration as your indoor air passes through the filter more frequently
  • Reduced fuel use because the furnace isn’t producing excess heat

If you need further guidance on choosing or maintaining two-stage heating in your home, contact us at Climatic Conditioning Co., Inc. We proudly serve homeowners around Sarasota, Bradenton and Lakewood.