Short answer
Preventing mold in Florida means controlling moisture, and humidity is the biggest lever. Keep indoor relative humidity in a reasonable range — generally below 60%, with many building-science practitioners targeting roughly 45–55% — by running efficient air conditioning, fixing leaks quickly, maintaining the HVAC and condensate line, ventilating baths and kitchens, and addressing standing water fast.
Humidity is the master control
Mold does not grow without moisture, and in Florida the largest source of ambient moisture is humidity itself. Control the humidity and you remove the conditions mold needs across the whole home at once, rather than chasing one damp spot at a time.
The widely cited guidance is to keep indoor relative humidity below 60%. Many practitioners aim tighter — roughly 45 to 55% — which stays comfortable while keeping surfaces dry enough to discourage growth. A simple hygrometer lets you see where your home actually sits.
Make your air conditioning do its second job
In Florida, the AC is your primary dehumidifier. A system that is maintained and correctly sized removes humidity as it cools; one that is oversized or short-cycling cools the air without wringing out the moisture. If a home feels cool but clammy, the system may not be dehumidifying well.
Keep the condensate line clear, change filters, and service the unit. In very humid conditions or in closed-up seasonal homes, a standalone dehumidifier can carry the load the AC cannot.
Ventilate where moisture is generated
Bathrooms, kitchens, and laundry areas produce bursts of moisture. Use exhaust fans that vent outdoors — not into an attic — during and after showers and cooking, and give them time to clear the air. Small habits here prevent the repeated damp cycles that grow "mildew" on bathroom walls and ceilings.
Fix water fast and watch the usual suspects
Correct leaks quickly — a slow drip behind a cabinet or at a roof penetration keeps materials wet long enough to grow mold. Keep an eye on the common trouble spots: under sinks, around tubs and showers, at the water heater and washing machine, at windows and roof flashings, and at the HVAC drain pan and condensate line.
Address any standing water within the first day or two. On wet porous materials, growth can begin within roughly 24 to 48 hours, so speed matters.
Special case: homes that sit closed
Seasonal and vacation homes are a common Florida risk. A house closed for weeks with minimal cooling can see indoor humidity climb and settle on surfaces — a frequent cause of the musty odor owners discover on return. Leaving the AC set to a moderate temperature, or using a dehumidifier and a humidity monitor, keeps a vacant home from becoming a moisture problem.
When humidity keeps returning despite these steps, that is a signal to investigate why — a focused inspection can find a hidden source rather than leaving you to manage symptoms.