Why Is My House So Humid?
If your home in Richmond Hill, Savannah, or anywhere in Coastal Georgia feels muggy, sticky, or damp even with the AC running, you're not alone. Here's what's actually happening — and what to do about it.
High Humidity Is a Coastal Georgia Reality
Coastal Georgia averages 75–80% relative humidity for much of the year. Combine that with salt air, frequent storms, and an extended cooling season, and the moisture load on an HVAC system here is dramatically higher than in drier climates.
The ideal indoor relative humidity is 40–50%. When it climbs above 55%, you start to feel that sticky, oppressive sensation — even if the thermostat reads a perfectly cool 72°F. Persistent indoor humidity above 60% also encourages mold, dust mites, and warped wood floors.
Most homeowners assume their air conditioner removes humidity automatically. It does — but only when it's properly sized, properly maintained, and running for long enough cycles. Several common issues cause an AC to cool the air without removing enough water.
Top 7 Reasons Your House Feels Humid
Each of these can independently cause indoor humidity to stay too high. Often two or three are happening at once.
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Your AC is oversized for your home
An oversized unit cools the air quickly and shuts off before it has a chance to dehumidify. Short cycles = high humidity. Common in newer construction.
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Your AC is undersized or struggling
On the flip side, an aging or undersized unit can't keep up with the heat load and runs at lower capacity, also leaving moisture in the air.
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Dirty or clogged evaporator coil
When the indoor coil is coated with dust, it can't efficiently condense water vapor out of the air. A common find during our 24-point Comfort Club inspection.
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Refrigerant is low
Low refrigerant lowers coil temperature inefficiently, reducing the AC's ability to pull humidity out. It also usually signals a leak that needs repair.
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Clogged condensate drain
If the drain line is clogged with biofilm, water backs up and can re-evaporate into your home instead of draining outside.
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Ductwork leaks pulling humid attic air
In Coastal Georgia attics, leaky return ducts suck in 100°F, 90%-humidity attic air and circulate it through your house. Surprisingly common.
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No dedicated dehumidifier
In our climate, many homes benefit from a whole-house dehumidifier integrated with the HVAC system — especially during shoulder seasons when the AC barely runs.
Why Humidity Stays High Even When the AC Runs
The most counter-intuitive cause is an oversized AC. Builders often install a system one or two tons larger than the home actually needs. The result: the room hits the thermostat set-point in 5–7 minutes, the system shuts off, and barely any water has been removed from the air. You feel cold and sticky at the same time.
The fix isn't always replacement. Sometimes a variable-speed blower upgrade, a thermostat that supports longer cycles, or a dedicated whole-house dehumidifier can solve the problem at a fraction of the cost. We'll measure the actual load on your home (Manual J calculation) before recommending anything.
Signs You May Need a Whole-House Dehumidifier
Whole-house dehumidifiers integrate with your existing ductwork and run independently of the AC, giving you precise humidity control year-round.
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Humidity stays above 55% with the AC on
If a hygrometer confirms persistently high humidity even when the AC is cooling, supplemental dehumidification is the right tool.
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Condensation on windows or AC vents
Visible water on cold surfaces inside means moisture is saturating the indoor air.
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Musty smell, especially in closets or basements
Mold and mildew thrive above 60% RH. The smell is the early warning.
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Allergy symptoms worsen indoors
Dust mites and mold spores both flourish in high humidity. A whole-house dehumidifier reduces both.
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Wood floors cupping or warping
Hardwoods absorb humidity. Persistent high humidity will cup and warp them — expensive damage compared to the cost of dehumidification.
Tired of a Humid House?
Our Coastal Georgia HVAC technicians diagnose the actual cause — not just guess — and recommend the right fix. Most appointments turn into same-day diagnosis.
Frequently Asked Questions
Why is my house so humid with the AC on?
Most often it's because the AC is oversized and short-cycling, the evaporator coil is dirty, refrigerant is low, or ductwork is leaking humid attic air into the system. Our technicians can diagnose which of these is happening with a single visit.
What humidity level should my house be at in summer?
Aim for 40–50% relative humidity. In Coastal Georgia summers, anything below 55% feels comfortable. Above 60% encourages mold and dust mites.
Will running the AC longer reduce humidity?
It can, if the unit is properly sized. Longer cycles give the coil more time to condense water out of the air. Setting fan to AUTO (not ON) is critical — running the fan continuously re-evaporates condensed water back into the home.
Do I need a whole-house dehumidifier in Coastal Georgia?
Many Richmond Hill and Savannah homes do, especially newer construction with tight envelopes and oversized AC. We can install a whole-house unit that integrates with your existing ductwork.
How much does a whole-house dehumidifier cost to install?
Most installs range from $1,800 to $3,200 depending on home size and ductwork configuration. We provide free in-home estimates with no obligation.
Can high humidity damage my home?
Yes. Persistent humidity above 60% causes mold growth, warps hardwood floors, encourages dust mites, peels wallpaper, and accelerates the deterioration of furniture and electronics.