Keeping an Orlando house dry
Most recurring mold in Central Florida houses is a humidity problem. The EPA says to keep indoor relative humidity below 60 percent, ideally 30 to 50. Outdoors, Orlando averages 137 days a year with a 70°F dew point. The gap between those is the AC's job.
Buy a gauge
A digital hygrometer costs about as much as lunch. Put one in the main living area and one in the room that smells worst. If it reads above 60 percent for days at a time, mold is a matter of when. Under 50 is comfortable and dry.
Thermostat habits
- Don't set it too high in summer. At 80°F and above, many systems barely run on humid days, and the house holds water. A few degrees lower often fixes a musty house.
- Use "auto," not "on," for the fan. With the fan on all the time, water on the coil blows back into the house between cooling cycles.
- Don't switch it off when you travel. A closed house in August with no AC can grow mold on furniture and closet contents in a couple of weeks. Set it higher than usual, not off, or use a dehumidifier setting if the thermostat has one.
When the AC can't keep up
- Oversized systems cool fast and shut off before they remove much water. A properly sized replacement, or a variable-speed system, runs longer and dries better.
- A whole-house or portable dehumidifier takes the water out without overcooling. Useful in a closed-off room, a converted garage, or a house that's cold but clammy.
- Leaky ducts in a hot attic pull humid air in. A duct test and sealing can be cheaper than you'd think.
- A clogged condensate line stops the system from dumping the water it collected. A float switch shuts the system off before the pan overflows.
Most of this is work for a licensed air conditioning contractor, not a mold company. AC and duct mold.
Room by room
- Bathrooms: run the exhaust fan during showers and for 20 minutes after, and check that it vents outside, not into the attic.
- Closets on outside walls: leave a gap between clothes and the wall, keep the door open sometimes, and don't store damp things.
- Laundry: vent the dryer outside and check the washer hoses every year.
- Kitchen: use the range hood if it vents outside.
Days with a dew point of 70°F or more, by month
Questions Orlando homeowners ask
What humidity should my house be in Florida?
The EPA says below 60 percent relative humidity, ideally between 30 and 50 percent. In an Orlando summer that takes the AC running long enough to dehumidify, and sometimes a dehumidifier.
Should I turn my AC off when I go on vacation in Florida?
No. Set it higher than usual instead. A closed house with the AC off in summer can climb well past 60 percent humidity, and mold can grow on furniture, closets and walls in a couple of weeks.
Does running the AC fan on prevent mold?
Usually the opposite. With the fan set to on, water left on the cooling coil between cycles evaporates back into the house. Auto is the better setting for humidity.