Variable Speed Furnaces | Everything Homeowners Need To Know

HVAC Logo IconBy HVAC.comJuly 30, 2023

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Variable Speed Furnace

Today’s furnaces incorporate innovative technology to deliver high energy efficiency levels and optimal comfort in homes across the world. Variable speed furnaces do just that, reducing energy consumption while delivering better temperature control and air quality.

If you’re searching for a new heating system, variable speed furnaces should be considered. Here’s what homeowners should know about using this technology for better heating at home.

What Are Variable Speed Furnaces?

Variable speed furnaces contain an ECM (electronically commutated motor) blower motor, which allows the furnace to operate at higher efficiency levels. They are DC motors that use a built-in inverter and magnet rotor, delivering better energy efficiency than furnaces with AC motors.

How Do Variable Speed Furnaces Work?

Variable speed furnaces are able to run at a range of speeds, rather than one speed as traditional furnaces do. The differing speeds control heating and cooling airflow through the home. Throughout operation, the furnace monitors incoming data from your HVAC system to automatically make blower motor speed adjustments.

Variable Speed Furnace Efficiency

The variable speed furnace delivers the proper amount of airflow based on the heating and cooling needs of your home. It accounts for the amount of air in circulation for precision airflow. The system also accounts for blocked vents and dirty furnace filters, and adjusts fan speed as needed to compensate.

Variable speed furnaces only operate at full speed when conditions call for it. With the ability to operate at lower speeds while still outputting adequate heating and cooling, the furnace requires much less energy to do the same job as a conventional furnace that operates at a single speed.

Unlike a conventional furnace, variable speed furnaces don’t wait for temperatures in the home to drop before they cycle back on. This gives occupants more consistent temperatures throughout the home, maintaining steady temps throughout the day.

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Indoor Air Quality with Variable Speed Furnaces

In addition to better energy efficiency and temperature control, variable speed furnaces deliver better air quality as a result of varying blower motor speed. Running the heating system’s fan continuously allows the furnace’s blower motor to continue air circulation even when heating is not required.

The variable speed furnace’s motor operates at low, efficient speeds to keep moving air through the home. Continued airflow keeps air cycling through your furnace filter, which allows more contaminants to be trapped in the filter and removed from your home’s air supply.

Variable speed furnaces also offer better indoor humidity control versus conventional furnaces. Variable speed furnaces are better at removing humidity from the air. This moisture protection works to prevent high humidity issues indoors, such as mold and mildew growth as well as increased allergen concentrations.

Variable Speed Furnace Price

Higher efficiency HVAC equipment typically comes with a higher initial price tag compared to lower efficiency options. The actual cost of furnace installation depends on the model you select plus labor and other considerations necessary for proper installation of your new furnace.

Even though they cost more upfront, the investment is worth it due to the energy savings variable speed furnaces achieve. Variable speed furnaces consume less energy than conventional furnaces, therefore your heating and cooling costs are cut considerably. Variable speed furnaces have a payback period of approximately four to five years – this means your new variable speed furnace pays for itself through generated energy savings in just a handful of years!

Learn More About Variable Speed Furnaces on is the world’s leading resource website for all things heating, cooling, and indoor air quality. We proved a plethora of resources to help homeowners better understand their heating, cooling, and IAQ options as well as the equipment in their homes.

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