A common assumption after water damage in a Jacksonville home is that running the A/C harder will dry the structure. The A/C, after all, removes moisture from the air as part of its normal operation. In a Florida summer, it pulls gallons of water out of the home every day. So why would water damage require anything beyond turning the thermostat down a few degrees? Because residential A/C is not a structural drying tool. It is a comfort tool that happens to remove some humidity as a side effect. After a real water event, A/C alone cannot move moisture out of saturated materials fast enough to prevent secondary damage — and in Florida humidity, the gap between what A/C can do and what the structure needs is wider than almost anywhere else in the country.
This post walks through why residential A/C is insufficient for structural drying, what dedicated dehumidification actually does differently, and why IICRC S500 specifies commercial dehumidifiers as part of the response.
Residential A/C is sized for comfort cooling, not structural drying — it removes about 1-2 pints of moisture per hour under typical conditions, while a saturated Florida home contains tens to hundreds of gallons of water trapped in materials. Commercial dehumidifiers used in restoration remove 100-200+ pints per day and operate continuously regardless of cooling load. Without dedicated dehumidification, evaporating moisture re-deposits on cooler surfaces and the drying never completes.
Understanding why A/C is not enough requires understanding what it does and how it does it.
A/C cools by passing room air across an evaporator coil colder than the air’s dew point. Moisture condenses on the coil and drains away as condensate. The system removes water from the air, but only the air that passes through the system during a cooling cycle, and only to the extent the coil is cold enough to drop the air below dew point.
Residential A/C runs to maintain a temperature setpoint, not a humidity setpoint. Once the thermostat is satisfied, the system shuts off. In Florida shoulder seasons (October-November, March-April), outdoor temperatures often allow the home to maintain setpoint without much A/C runtime — and during these periods, indoor humidity drifts up because the system is not running long enough to remove moisture. Some Jacksonville homeowners notice the home feels “muggy” during these months even with the A/C on.
A 3-ton residential A/C unit under typical Florida summer conditions removes around 1-2 pints of water per hour. That sounds like a lot. It is not, compared to what a wet structure contains. A medium-sized Jacksonville home with Category 1 water damage from a burst supply line might have 50+ gallons of water absorbed into building materials. At residential A/C rates, removing that water — even ignoring evaporation losses and ambient infiltration — would take weeks. Mold establishes in 24-48 hours.
The IICRC S500 standard calls for dehumidifiers sized to the affected area volume and the moisture load. The equipment is fundamentally different from residential A/C.
LGR units use refrigerant technology similar to A/C but optimized for moisture removal rather than temperature reduction. They operate efficiently at lower temperatures and continue functioning when standard refrigerant units lose efficiency. A typical commercial LGR unit removes 100-150 pints of water per day under restoration conditions — 50-100x what a residential A/C dehumidifies as a cooling side-effect.
Desiccant units use a moisture-absorbing material (typically silica gel or molecular sieve) that captures water from the air and releases it through a separate heated airstream. Desiccants operate effectively at lower temperatures and lower humidity levels than refrigerant units, making them the equipment of choice during winter restoration jobs or in spaces too small to support an LGR unit.
Restoration dehumidifiers run 24/7 throughout the drying period, regardless of cooling load or ambient temperature. Residential A/C cycles based on the thermostat. The continuous operation maintains pressure differentials that pull moisture from saturated materials into the air where the dehumidifier can capture it.
A common DIY response after water damage is to set up fans and open windows. In Florida, this almost always extends the problem rather than solving it.
Air movers (high-velocity fans used in restoration) accelerate evaporation from wet materials. But evaporated moisture has to go somewhere. Without dehumidification, the moisture stays in the air and re-deposits on cooler surfaces nearby — often the very walls, framing, or flooring that was being dried. The drying clock starts over.
Opening windows in a Florida summer to “air out” wet conditions pulls in outdoor air that NOAA records show averages around 75% relative humidity. The incoming air is wetter than dry-standard indoor conditions, so the home gains humidity rather than losing it. Effective drying requires sealing the affected area and conditioning it with dehumidifiers.
In dry climates (Arizona, parts of California), running fans alone can produce significant drying because the ambient air absorbs evaporating moisture and carries it outdoors through natural ventilation. In Florida, the ambient air is already near saturation, so this passive drying path is closed. Active dehumidification is not optional here — it is the entire mechanism.
The standard prescribes calculations based on affected area, material types, and ambient conditions. The result is a measurable, monitored process rather than an ad-hoc effort.
Dehumidifier capacity is matched to the volume of the affected area and the moisture load. Typical residential water damage in Jacksonville requires 1-3 LGR units for the affected area. Larger losses or commercial spaces scale up to multiple units operating in parallel.
Pin and pinless moisture meters take daily readings on affected materials. Hygrometers track ambient temperature and humidity. The data drives adjustments — adding equipment if moisture loss stalls, removing equipment if targets are reached, reconfiguring airflow if specific areas lag.
The drying ends when materials reach target moisture content verified at multiple measurement points and ambient conditions stabilize at dry-standard levels. The IICRC dry standard varies by material type — plywood sub-floor at 12-16%, drywall at 16% or below, framing lumber at 19% or below.
Residential consumer dehumidifiers typically remove 30-70 pints per day under ideal conditions and significantly less under real-world humidity. Restoration jobs in Florida often need 200-500+ pints per day of removal capacity to dry materials in time to prevent secondary damage. Multiple consumer units can supplement a job but cannot replace commercial equipment for primary structural drying.
Most Category 1 residential water damage in Florida requires 3-7 days of continuous dehumidification. Category 2 or 3 jobs with more demolition and substrate removal often run longer because the exposed cavities need to dry as well. The job closes only when monitoring confirms target moisture content reached.
Yes, modestly. Commercial dehumidifiers draw substantial power compared to residential equipment. Restoration teams typically document equipment runtime for insurance billing, which may include a power usage component depending on the policy and contract. Most Florida homeowners insurance covers reasonable restoration equipment costs as part of the covered loss.
You can typically leave. Restoration teams check the home periodically — usually daily — to verify equipment operation and take moisture readings. Some homeowners stay through the process; others arrange temporary lodging if the affected area makes the home uncomfortable. EPA guidance recommends keeping pets away from active restoration areas and minimizing time in heavily contaminated zones until cleanup completes.
In Florida, natural drying typically does not return materials to dry-standard moisture content. The structure may feel dry on the surface while substrate moisture continues to feed mold growth. EPA mold guidance specifically identifies inadequate drying as one of the leading causes of post-water-damage mold remediation jobs.
Your home’s A/C is good at what it does — keeping the indoor air comfortable. It is not designed to dry a structure that just absorbed dozens of gallons of water, and in this climate the gap between what residential equipment can deliver and what the structure needs is too wide to bridge with thermostat changes. Commercial dehumidification, monitored under IICRC S500, is what closes that gap.
Rainbow Restoration of Deerwood deploys LGR and desiccant dehumidifiers across the Jacksonville metro — Southside, Atlantic Beach, and St. Augustine — sized to Florida humidity loads rather than generic national equipment specs. Our water damage restoration team operates equipment continuously during the drying phase and verifies moisture content against the IICRC standard before closing. When mold has already established because previous water events were inadequately dried, the mold remediation team picks up the IICRC S520 work as a continuous project.
After water damage in Florida, the question is not “is the A/C running?” — it is “does the moisture content prove the structure is dry?” Only equipment built for the job can answer the second question with data.
