Heating, ventilation and cooling (HVAC) system blowers are often classified according to their motor. The blower, of course, is responsible for circulating air through the ductwork. It pulls air into the return vents, and it pushes conditioned air out the supply vents. While some blowers have a single-speed motor, though, others have a variable-speed motor.
What Is a Variable-Speed Blower?
A variable-speed blower is a type of HVAC blower that can operate at different speeds. It’s characterized by the use of an electronically commuted motor (ECM). ECMs are highly efficient motors that feature an inverter and a permanent magnet. This design allows them to run at different speeds.
Most blowers are powered by either an ECM or a permanent split capacitor (PSC) motor. ECMs can run at different speeds, whereas PSCs can only run at a single speed. As a result, blowers with an ECM are known as variable-speed blowers. Blowers with a PSC, on the other hand, are known as single-speed blowers.
Air Conditioning and Heating
Some homeowners assume that blowers are only used in air conditioning systems. When running your air conditioning system, the blower will circulate air through the ductwork. It will also circulate air through the ductwork, however, when running your furnace.
Blowers are typically installed in the furnace or an air handling unit (AHU). Whether powered by an ECM or PSC motor, the blower will circulate air through the ductwork. It will turn on automatically whenever you run your air conditioning system or your furnace. Alternatively, you can force the blower to turn on by setting your thermostat’s fan to the “ON” position.
Variable-Speed Blower Benefits
If you’re looking to upgrade your HVAC system with a new blower, you may want to choose a variable-speed blower. Variable-speed blowers are more efficient than single-speed blowers. They don’t run at full capacity all the time. Instead, variable-speed blowers will gradually increase or decrease their operational speed to maintain your desired comfort level. The end result is greater energy efficiency.
You can save money by switching to a variable-speed blower. Because they are more energy efficient than single-speed blowers, they cost less to run. So, while upgrading to a variable-speed blower requires an investment, it can pay off in the long run.
You may discover that variable-speed blowers are quieter than their single-speed counterparts. When a single-speed blower initially turns on, it will run at full speed. You can typically hear it turning on and running. Variable-speed blowers are quieter.
