Why Is My House Still Humid With the AC On? Fort Lauderdale, FL

BW Air Conditioning

6 days ago

3 min read

The short answer: if your house feels sticky even though the AC is running, the system is usually cooling the air without removing enough moisture. The most common causes in Fort Lauderdale are an oversized unit that short-cycles, a dirty coil or filter, a clogged condensate drain, leaky ducts, or a thermostat fan set to ON. Most of these are fixable.

Your air conditioner is also your main dehumidifier. It pulls moisture out of the air as warm, humid air passes over the cold evaporator coil, and the water drains away outside. When something interferes with that process, the thermostat can read 74 degrees while the room still feels clammy.

Residential air duct system in a Fort Lauderdale, FL home, where leaks and poor airflow can leave the house humid

Why Your House Feels Humid With the AC On

The unit is too big. An oversized system cools the air quickly and shuts off before it has run long enough to dehumidify. We cover this in detail in our guide to AC sizing in Fort Lauderdale.
A dirty filter or evaporator coil. Restricted airflow or a coated coil reduces how much moisture the system can remove. Regular professional AC maintenance keeps the coil clean.
A clogged condensate drain. If the water cannot leave, it can back up, overflow, or be reintroduced to the space. The EPA's mold guidance specifically advises keeping air conditioning drip pans clean and drain lines flowing.
Leaky ducts or return leaks. Ducts that pull in humid attic air or leak conditioned air can undermine dehumidification. A ductwork inspection can find them.
The thermostat fan is set to ON. With the fan running continuously, moisture that collected on the coil can be blown back into the house between cooling cycles. AUTO is usually the better setting for humidity.
Low refrigerant or a failing component. A system that is low on refrigerant or has a weak blower will not cool or dehumidify properly and needs a diagnosis.

What Humidity Level Should You Aim For?

The EPA recommends keeping indoor humidity below 60 percent, and ideally between 30 and 50 percent, to discourage mold. Their brief guide to mold, moisture and your home notes that a small, inexpensive humidity meter from a hardware store will tell you where you stand. In South Florida, holding the low end of that range during summer can take a well-matched system and sealed ducts.

Fort Lauderdale, FL homeowner whose air conditioning is running but the house still feels humid

What to Try Before You Call

Replace a dirty filter, set the thermostat fan to AUTO, make sure supply and return vents are open and unblocked, and run bathroom and kitchen exhaust fans when showering or cooking. Resist dropping the thermostat several degrees to compensate: that can make a system run longer but often leads to a colder, still-damp house and higher bills.

If the house stays humid after those basics, or you notice a musty smell, water stains, or condensation on windows, it is time for a professional look. Our technicians can check coil condition, drain lines, airflow and duct leakage during an air conditioning repair visit.

Frequently Asked Questions

Why is my AC running constantly but my house is still humid?

A system that runs nonstop without removing moisture may be undersized, low on refrigerant, restricted by a dirty filter or coil, or fighting leaky ducts. It needs an inspection rather than a lower thermostat setting.

Does a bigger air conditioner remove more humidity?

No. A larger unit usually removes less, because it reaches the temperature target and stops before it has dehumidified. Right-sized equipment running longer cycles is better for humidity.

Do I need a whole-home dehumidifier in Fort Lauderdale?

Not always. If the AC is properly sized, clean and the ducts are sealed, many homes do fine. Where humidity stays high, an add-on from our indoor air quality solutions can help.

Should the thermostat fan be on AUTO or ON?

AUTO is typically the better choice for humidity control in a humid climate, since the fan stops when the coil is wet and cooling is not running.

Get Your Humidity Under Control

BW Air Conditioning is a licensed air conditioning repair company serving Fort Lauderdale and Broward County, Florida license CAC029407, with more than 30 years of local experience. Call (954) 565-7369 or schedule service online and we will find out why your house feels sticky.