What’s Actually Happening with a Two-Stage Furnace?

two stage furnace system cincinnati ohio

Single-Stage vs. Two-Stage Furnace

Consider a single-stage furnace: as you might have guessed, your system has one speed it operates at with a single-stage furnace. A single-stage furnace also means your furnace is constantly working; it’s either at maximum air speed, or you are waiting for cooling to occur. Once the home does cool, then the furnace will start again when it’s a one-stage system.

With a more precise alternative, you can have the furnace adjust how hard it is working to match your specific needs. Rather than always running at full capacity and then shutting off (and then back on), a two-stage furnace is made up of two-stages of capacity: high and low.

This ability to go back and forth between these levels of operation results in consistent temperature and more even airflow. Just consider how the low setting on a two-stage furnace meets heating demands about 80 percent of the time.

What does this mean on a day-to-day basis? First, it means you have very even temperatures in your home, and people do not feel “air movement” most of the time, either. Many times, since it is not running at full speed, it is also very quiet. When you run your furnace at a lower speed, it really helps you have ultimate comfort!

Another way of thinking about a two-stage system is that when you need your furnace to work harder (extreme cold days), it will. When you don’t need it work harder (more mild days in the winter), however, it won’t. Many people who live in areas where temperatures can vary day to day enjoy this real-time benefit of greater control and efficiency. The benefits to having a full (or high) speed alongside a half (or low) speed, is not just in the winter. A two-stage system also means you can greater humidity control in your home during all months of the year.

Because your system can run at a low, optimal speed, it has greater ability to have more air pass through the system, and therefore more air contaminants can be captured.

Maintaining Your Furnace

Now that you know more about longer, low-capacity operation, and the benefits that are passed on to you, it’s time to examine what else you should know after installation.

What are some of the basics that you want to do to maintain your furnace so you can continue that high degree of efficiency and comfort?

Here’s a list to get you started:

  • Check electrical
  • Check carbon monoxide
  • Clean furnace or boiler
  • Check vent pipe to chimney
  • Clean and adjust burners
  • Check all safety devices
  • Inspect combustion chamber
  • Check/clean blower wheel
  • Check furnace wiring
  • Check hot water tank
  • Check gas valve operation
  • Test for any gas or heat exchanger/combustion chamber leaks
  • Check humidifier
  • Check motors and controls sequence
  • Check and fix of thermostat

Call the Experts at Greater Comfort

With more than 60 years of experience, our highly trained technicians can help you maintain your system and also answer any questions you have on our visit. If you are considering a two-stage furnace or need to get your maintenance in, give us a call today at 859-491-4915.


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