A mechanical engineer friend who designs air conditioning systems told me that ductless mini-split systems do not dehumidify well. Or in engineering speak: O/K for comfort cooling; not so good at latent removal.
I have found the opposite to be true if they are operated correctly. And regarding the whole building, they do not create pressure imbalances like many ducted systems nor are they plagued by duct leaks that tend to create a net humidity increase in Florida buildings.
Regarding settings: There is a humidity control setting displayed on the remote as a raindrop (see photo). This setting slows the fan during cooling mode which allows the coil to get colder. Colder coils condense more water vapor out of the air. The fan must be set on “auto” to get the full effect. Setting the fan to high instead of “auto” could have the opposite effect…poor humidity control as in the engineer friend’s example. Leaving the fan in “auto” is key because these inverter systems have a variable speed compressor which should match the fan speed even if not set to “dehumidify”.
A major upgrade in humidity control and energy efficiency is the Hyperion system from Daikin. Rather than battle condenser air with evaporator air like a Honeywell dehumidifier it subcools the liquid refrigerant in the process and is therefore more energy efficient. Either of these systems really wrings moisture out of the air. You can see it going out the drain. Now I am guilty of “engineer speak”.
Jay Hoover, Integrity Air Conditionins, Inc.