Variable Speed, Two-Speed, Single-Speed… What is the Difference?

If you are in the market for a new HVAC system, more than likely you have heard the terms Variable Speed, Two-Speed and single speed thrown around by contractors or friends. Here is a simple breakdown of the differences:

Like a light switch, the system is either on or off. These systems feature a fixed speed compressor that runs at 100% capacity to reach desired temperature then turns off.
PROS -Ability to meet desired air temperature when running at 100% capacity -Most affordable option
Similar to a fan switch, two-stage systems can be off, on low speed or high speed. These systems have a two-stage scroll compressor that modulates between either 65% capacity or 100% capacity allowing two levels of operation: high for hot summer days and low for milder days.
PROS – Longer runtimes provide more even temperature as well as removal of moisture from the air – Ability to efficiently shift to 100% to quickly meet desired temperature setting – Multiple compressor combinations offer additional stages of cooling capacity.
Variable Speed:
Variable speed systems modulate by varying the speed of the compressor motor, where capacity output increases and decreases with motor speed. These systems feature an indoor variable speed fan as well as the compressor that operates anywhere between 20-120% capacity/900-7,000 RPMs.
PROS – Wide turndown capability delivers more even and consistent temperature – Turndown to 900 RPM in cooling mode means less cycling and better dehumidification – 7,000 RPM overspeed capability in heating mode provides hot air supply even in extreme cold weather.
Simple Descriptions, but hopefully helpful if you are debating what kind of system you want in your home. Call us and let us come meet with you to see your home and discuss the right solution.

Take the Next Step

Contact Evergreen Heating and Cooling Today!


401 South 13th Street,
Waco, TX 76706





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