A variable-speed motor is an advanced technology utilized by modern HVAC systems. It allows your unit to run at different speeds depending on the output requirements. Unlike single-speed motors, which operate at full capacity, variable-speed motors adjust their output in increments. They can even adjust it to 1% increments for precise heating and cooling. This provides greater efficiency and energy savings down the line.
How Does a Variable-Speed Motor Work?
A variable-speed motor is connected to a variable-frequency drive (VFD). This monitors incoming power from the electricity provider and sends signals to the variable-speed motor to adjust its speed as required.
Instead of blasting on at 100%, the motor slowly ramps up its speed. Once the target temperature is reached, the motor slows down. It runs for longer periods at this lower speed to maintain the temperature, rather than shutting off entirely.
Are HVAC Units With Variable-Speed Motors Worth It?
While the upfront cost is higher than that of single-stage systems, the long-term benefits in terms of comfort and operational costs are significant.
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Enhanced Efficiency & Cost Savings
Running a motor at low speed requires less electricity than running it at high speed. Because these motors avoid the energy-intensive on/off cycling, they help lower bills considerably.
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Better Humidity Control
Variable-speed motors run for longer cycles at lower speeds, which results in the air passing over the evaporator coil more consistently. This allows the system to pull much more moisture out of the air compared to a system that quickly shuts down.
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Consistent Comfort
Single-speed motors result in temperature swings. For instance, when the house gets too cold, the cooling unit turns off; when the house gets too hot, the unit turns on. Unlike single-speed motors, variable-speed motors maintain a consistent temperature.
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Better Air Quality
Since the fan runs almost continuously at a low speed, air is constantly being cycled through the air filters, capturing more dust and pollutants.
