10 Everyday Habits That Make Mold Worse in Florida Homes (And Which "Tips" Don't Apply Here)

I saw a list going around social media recently: "10 daily habits that can make mold worse." Most of it was solid. But at least one tip on that list would actively *cause* mold problems here in Northeast Florida — and that's the problem with national advice. Mold behaves differently in Jacksonville, Clay County, and St. Johns County than it does in Ohio.

So here's that list again — reviewed by a Licensed Mold Assessor who inspects homes in this climate every week, with the Florida corrections where they're needed.

First, the one to ignore in Florida

Open your windows and blinds every day. Up north, airing out the house lowers indoor moisture. Here, for most of the year, it does the opposite. When it's 90 degrees with 70% humidity outside, opening windows pumps moist air into a cool house — and that moisture condenses on cold surfaces, in walls, and inside your ductwork. In Florida, your air conditioner is your dehumidifier. Keep the windows closed, let the AC run, and aim for indoor humidity between 45 and 55 percent. (Blinds open for sunlight? Absolutely. Windows open in July? No.)

The nine habits that genuinely feed mold — here and everywhere

1. Not running the bathroom exhaust fan — or shutting it off too soon. A hot shower dumps a pint or more of water vapor into a small room. Run the fan during the shower and for 20–30 minutes after. If your fan can't hold a square of toilet paper against the grille, it's too weak to matter — a common find in the homes I inspect.

2. Letting damp towels, clothes, and bath mats sit. Mold can establish on damp fabric in 24–48 hours. Hang towels spread out, wash bath mats regularly, and never leave wet laundry in the machine overnight.

3. Skipping the kitchen vent hood. Boiling a pot of pasta releases moisture just like a shower does. If your hood vents outside, use it. If it just recirculates, run the AC fan and keep an eye on nearby cabinet interiors.

4. Running humidifiers blind. Honestly, most Northeast Florida homes should not run a humidifier at all. If someone in your house uses one for medical reasons, put a $10 hygrometer in the room and keep it under 50%.

5. Ignoring condensation on windows and AC vents. Water beading on windows or sweating on supply vents is your house telling you the humidity is too high or air is leaking somewhere it shouldn't. Wipe it up, then find the cause — don't just keep wiping.

6. Blocking vents with furniture or rugs. Every blocked supply or return creates a dead-air pocket, and stagnant air plus humidity is exactly the recipe mold wants. This is one of the most common conditions I flag in occupied homes.

7. Sealing off closets and unused rooms. Closing a room's door and vents to "save on cooling" turns it into an unconditioned box inside your house. Closets on exterior walls are notorious for this — that musty smell in the guest closet is not a coincidence. Leave doors cracked and let conditioned air circulate.

8. Cooking, showering, mopping — with the AC set to "off" instead of "auto." If the system never runs, it never dehumidifies. In our climate, a house that sits closed up with no AC for even a week (hello, vacation season) can come home musty. Set it to 78–80 while you're away, not off.

9. Ignoring small leaks and moisture under sinks. The slow drip under the kitchen sink does more mold damage than most roof leaks, because nobody sees it for months. Check under every sink quarterly. Dark stains, swollen cabinet floors, or a musty smell mean it's been wet longer than you think.

When habits aren't the problem

If you're doing all of this and still smell mustiness or see recurring spots, the source is usually something a homeowner can't see — a duct leak, an attic ventilation problem, a slow plumbing leak inside a wall, or an AC system that's oversized and short-cycling. That's when testing beats guessing.

I'm a Licensed Mold Assessor serving Jacksonville, Clay County, St. Johns County, and the surrounding Northeast Florida area. A mold assessment gives you clear answers and documentation — not a scare pitch. If something in your home doesn't smell right, Schedule and Assessment with Hanna Home Services; call/text 904-658-1009.