The thermostat reads 74 degrees. The AC has been running for hours. Yet the air in your Fort Lauderdale home still feels heavy, the windows carry a faint film of condensation, and something musty lingers in the hallway. It’s easy to assume the air conditioner is broken. But you may be diagnosing the wrong system entirely.
At Edd Helms Electric & Air Conditioning, we’ve been working in South Florida’s climate since 1975. One of the most common calls we receive goes something like this: the system is cooling, the electric bill is climbing, and the house still feels clammy. Understanding why requires understanding what an air conditioner actually does. Just as importantly, it requires knowing what it was never designed to do.
Why Your AC Cools the Air Without Drying It
An air conditioner removes moisture from the air as a side effect of cooling, not as a dedicated function. When warm indoor air passes over the evaporator coil, the coil’s cold surface causes moisture to condense on it, much like a cold glass sweating on a summer afternoon. That condensed water drains out through the condensate drain line. Dehumidification happens, but only while the system is actively running and the coil stays cold enough to trigger condensation.
The problem surfaces on mild but humid days. When outdoor temperatures aren’t extreme, your system can satisfy the thermostat’s temperature setpoint quickly and shut off before it’s run long enough to pull meaningful moisture from the air. This pattern (known as short cycling) leaves the indoor temperature comfortable but relative humidity elevated. You feel cool and sticky at the same time, which is exactly as unpleasant as it sounds.
The EPA identifies 60% relative humidity as the threshold above which mold can begin growing on organic surfaces such as drywall, wood framing, and fabric. The agency’s recommended indoor comfort range is 30% to 50%. A home sitting at 65% or 70% relative humidity isn’t just uncomfortable. It’s accumulating biological risk while the thermostat shows a perfectly acceptable temperature.
Why Fort Lauderdale Makes This Problem Worse
Part of what makes this so persistent here is the raw humidity load the outdoor environment places on every home in the area. During South Florida’s wet season (roughly June through September), outdoor relative humidity routinely exceeds 80%. That moisture presses against every door frame, window seal, and wall penetration in your home continuously. Fort Lauderdale’s average relative humidity across the full year ranges from about 67% to 78%, with peaks well above that during summer afternoons following rain. No air conditioner sized for normal cooling loads was engineered to dehumidify air at those concentrations while simultaneously holding a comfortable temperature.
A substantial share of Fort Lauderdale’s residential housing predates 1980 and is built using concrete block and stucco on slab foundations. This construction type, common throughout Broward County, is prone to moisture migration through the block itself and up through the slab. In older homes especially, moisture doesn’t just enter through windows and doors. It moves through the structure. An AC that’s working perfectly can’t address moisture that’s entering through the walls and floors.
Fort Lauderdale earned its nickname the “Venice of America” from the approximately 165 miles of navigable canals that run through the city. A large share of homes sit directly adjacent to those canals, which means constant ambient evaporation at the property line. Canal-adjacent homes carry a higher baseline moisture load than homes several blocks inland, and that difference shows up on the indoor humidity gauge regardless of how new or efficient the AC system is.
Signs You Need a Repair, Not Just a Dehumidifier
Before concluding that your home’s humidity is a climate-load problem, a licensed technician should rule out the maintenance and settings issues that produce the same symptoms. One of the most common is the thermostat fan setting. When the fan is set to “ON” instead of “AUTO,” the blower runs continuously even when the compressor has cycled off, re-evaporating moisture that already condensed on the coil and returning it to your living space. Switching from “ON” to “AUTO” costs nothing and can produce a measurable humidity improvement within hours.
Beyond the fan setting, these are the repair-side causes a technician should check:
- Dirty air filters: Restricted airflow reduces the time air spends in contact with the evaporator coil, lowering both cooling and dehumidification efficiency.
- Dirty evaporator coils: A film of dust and debris on the coil insulates it, preventing efficient condensation and moisture removal.
- Clogged condensate drain lines: A blocked drain causes water to back up, sometimes re-evaporating into the airstream or triggering the system to shut off on a safety float switch.
- Low refrigerant charge: Insufficient refrigerant raises coil temperatures, reducing condensation and leaving humidity elevated even when the system appears to be cooling normally.
If fan settings, filters, drainage, and refrigerant have all been confirmed as serviceable and the system is appropriately sized for the home, the remaining moisture load is a climate and building issue. At that point, repair alone won’t resolve it.
Whole-Home Dehumidification: Built for What AC Wasn’t
A whole-home dehumidifier solves the problem at the mechanism level rather than asking a cooling system to do a job it wasn’t designed for. Unlike a portable room unit, a whole-home dehumidifier installs directly into the existing ductwork and treats air across the entire living space. It operates independently of the thermostat’s temperature call, targeting a humidity setpoint directly. When indoor relative humidity climbs above your target, the dehumidifier runs. The AC’s job stays where it belongs: managing temperature. For homes near canals, for older concrete block construction, and for anyone who’s worked through the repair checklist and still can’t get below 60% relative humidity, this is the right solution.
We’re an authorized dealer for Trane®, Rheem®, and Ruud®, and we install dehumidification equipment from these manufacturers. New installations carry a one-year warranty, and labor or repair work carries a 30-day warranty, so you know exactly what’s covered after the work is done.
Where to Start
The most useful first step is also the cheapest: pick up an inexpensive hygrometer at any hardware store (typically under $15) and check your indoor relative humidity. Consistently above 50% means you’re past the EPA’s comfort threshold. Above 60%, mold becomes an active risk. That single reading also tells a technician immediately whether you’re dealing with a repair issue, a sizing issue, or a humidity load the AC genuinely can’t handle on its own. If the number stays above 60% after you’ve adjusted the fan setting and replaced the filter, it’s time for a professional assessment. We offer same-day service and 24/7 emergency availability, and our technicians can walk through both the repair-side checklist and the dehumidification options that fit your home’s construction and location. Give us a call at (954) 838-5559.