How to prevent mold in a Florida home

Keep indoor relative humidity below 60%, ideally between 30% and 50%. EPA gives that range, CDC says keep it no higher than 50% all day, and Florida DOH says below 60% with below 50% best because it also controls dust mites. ASHRAE's engineering target is a maximum dew point of 60 F during unoccupied hours, with sustained gypsum-board moisture above 15% or indoor dew point above 60 F as early warning signs. Multiple measures beat one reading.

Yes, that is part of how it works. Warm humid air passes over cold evaporator coils, moisture condenses and drains away before cooler drier air is recirculated. Two habits matter: keep the fan on AUTO rather than ON, because FSEC experiments measured lower indoor humidity in AUTO, and avoid an oversized unit, because moisture removal does not reach full capacity for roughly the first three minutes of a cooling cycle, so shorter cycles remove less water.

Only if your AC cannot keep humidity in range. EPA puts the target below 60% relative humidity, ideally 30% to 50%, and says that if you have a central AC system and need a dehumidifier to stay below 60%, the air conditioning system should be examined for problems. Check the drain pan, drain line, filter, refrigerant charge and sizing before buying a bigger dehumidifier. A humidistat can switch the HVAC on automatically when humidity rises.

Run the exhaust fan or open a window when showering, and use exhaust fans or open windows when cooking, running the dishwasher or washing dishes. Vent moisture-generating appliances such as clothes dryers, stoves and kerosene heaters to the outside where possible, because combustion appliances add water vapor unless vented out. FSEC suggests interlocks or timers so bathroom fans are not left running, or humidistat control, and kitchen and bath fans should run while cooking or bathing.

Fix water before it becomes growth. EPA advises fixing leaky plumbing and building-envelope leaks as soon as possible, watching for condensation and wet spots, cleaning and repairing roof gutters regularly, and making sure the ground slopes away from the foundation so water does not enter or collect. Keep AC drip pans clean and drain lines unobstructed, and reduce humidity. That combination addresses the moisture mold needs; cleaning growth without these fixes only hides the problem for a while.

Fix the moisture or it will return. Cleaning removes what you can see, but the water source keeps feeding new growth, which is why EPA and Florida DOH focus on moisture control and removal rather than killing mold. Dead mold can still cause allergic reactions, and bleach is not recommended as a routine treatment. Dry the area fast, correct leaks and condensation, keep humidity below 60%, and check the repair after the next heavy rain.

There is no official season, but the wet months are the risk window. NOAA monthly normals for Miami show June at 10.51 inches, August at 9.58 and September at 10.22, against roughly 1.8-3.5 inches in the dry season. Dew points are at or above 70 F from June through September. EPA's guidance to dry water-damaged materials within 24 to 48 hours applies all year.