Quick answer
A whole-home dehumidifier is a ducted unit installed alongside the air handler that removes moisture from the air independently of cooling. In Miami it keeps indoor relative humidity near 45 to 50 percent, which stops mold growth, reduces dust mites, and lets you feel comfortable at a higher thermostat setting.
Written by Sylvia Denton, HVAC Guides Editor. Updated 2026-09-22.
Air conditioners remove moisture as a side effect of cooling. When the system runs long and steady, it pulls plenty of water out of the air. But on mild, muggy days in spring and fall, after a rain shower, or in homes where the AC is oversized and short-cycles, the thermostat is satisfied long before the humidity is. The result is a house at 75 degrees and 65 percent humidity, which feels clammy and grows mold.
A whole-home dehumidifier solves that by working on moisture alone. It connects to the duct system, pulls air from the return, dries it and sends it back into the supply. A dedicated humidistat controls it, so it runs when the air is wet whether the AC is cooling or not. The water drains to the same condensate line as the air handler.
The comfort change is often bigger than people expect. At 50 percent humidity, 77 degrees feels like 74, so many homeowners raise the thermostat and save on cooling while feeling better.
