Florida Air Duct & Dryer Vent Cleaning, With Humidity in Mind

The most humid state in the nation

NOAA calls Florida the most humid state in the nation, with hot, humid summers and mild winters. Average January temperatures range from the lower 50s°F in the north to the upper 60s°F in the south, and more of the state's rain falls in the warmer months of June through September.

Every one of Florida's 67 counties falls in the Department of Energy's Building America hot-humid climate region. Under the 2021 IECC, Miami-Dade, Broward, Monroe, and Palm Beach counties are in climate zone 1A (Palm Beach was moved there from 2A in the 2021 edition), and the rest of the state is zone 2A.

Sources: NOAA NCEI — State Climate Summaries 2022: Florida; PNNL for U.S. DOE Building America — Guide to Determining Climate Zones by County (PNNL-33270, 2022)

Humidity, condensation, and your system

In a humid climate, moisture matters more to a duct system than dust does. EPA identifies condensation on or near air conditioner cooling coils as a major factor in moisture contamination of the system, and says controlling moisture is the most effective way to prevent biological growth in air ducts.

UF/IFAS Extension recommends keeping indoor relative humidity below 70 percent — ideally between 45 and 60 percent — and notes that humidity above 70 percent for long periods can eventually lead to mold problems. It also points out that during very humid weather, especially rainstorms, the air conditioner often doesn't run long enough to control indoor humidity.

Sources: U.S. EPA — Should You Have the Air Ducts in Your Home Cleaned?; UF/IFAS Extension — Energy Efficient Homes: Indoor Air Quality and Energy (FCS3275)

Where the equipment sits

Central air is the norm here: in the Energy Information Administration's 2020 Residential Energy Consumption Survey, about 90 percent of occupied Florida homes used central air conditioning (67 percent nationally), and main heating was split between furnaces (33 percent) and central heat pumps (31 percent).

Florida Solar Energy Center research describes attic air handlers as a common practice in much of the southern U.S., and measured attic air temperatures above 130°F in a Florida test home in summer. Air handlers can also sit in a garage or an indoor closet, which changes how a technician reaches the system.

UF/IFAS Extension notes that ducts in unconditioned attics or garages waste energy if they're poorly insulated, that typical duct systems lose 25 to 40 percent of the heating or cooling energy they carry, and that an improperly sealed air handler in a garage can pull in poor-quality outdoor air or vapors from the garage. Cleaning doesn't seal or insulate ducts — that's HVAC contractor work.

Sources: U.S. EIA — 2020 RECS: Highlights for air conditioning in U.S. homes by state; U.S. EIA — 2020 RECS: Highlights for space heating in U.S. homes by state; Florida Solar Energy Center (UCF) — Performance Assessment of Photovoltaic Attic Ventilator Fans (FSEC-GP-171-00); UF/IFAS Extension — Energy Efficient Homes: The Duct System (FCS3263)

Hurricanes and flooding

NOAA reports that hurricane-force winds affect Florida an average of three times every five years. If flood water reaches your heating and cooling system, EPA advises not using it to help dry out the house.

EPA also says insulated ducts whose insulation gets wet or moldy can't be effectively cleaned and should be removed and replaced. Flood restoration and mold remediation are separate services we don't provide.

Sources: NOAA NCEI — State Climate Summaries 2022: Florida; U.S. EPA — Flood Cleanup to Protect Indoor Air and Your Health; U.S. EPA — Should You Have the Air Ducts in Your Home Cleaned?