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Variable spped indoor units are usually quieter.

Variable speed indoor units will dehumidify better when set to enhanced
mode.

Variable speed blower motors are more efficient than standard motors

Variable speed blower motors are more powerful than standard motors in
most applications. They will help overcome minor duct restrictions and
high resistance air filters.


If humidity is a problem, Trane/American Standard has some of the
lowest sensible heat ratios (SHR) in the industry. That means they
dehumidify better.
NOTE: This assumes they are installed properly, refrigerant charge &
air flow are correct and unit is not oversized! It is also important
to seal any ducts that are outside the thermal envelope/pressure
envelope of the house.

Stretch