South Carolina summers are no joke. Alongside the blazing heat comes another major issue: lots of humidity. While your air conditioning system is designed to keep your home cool, excess moisture in the air can make it work overtime, reduce its effectiveness, and even lead to breakdowns. At Prestige Heating & Air, we’ve seen what unchecked humidity can do to both your home and your HVAC system.

The good news is that, in this blog, our Charleston HVAC team will share some practical steps you can take to protect your AC, your comfort, and your wallet.

Why Humidity and AC Systems Don’t Get Along

Humidity refers to the amount of moisture in the air. The higher the humidity, the more difficult it becomes for your body (and your AC) to cool things down. Your AC doesn’t just cool the air—it also removes some of that moisture. But when humidity levels are too high for too long, it can:

  • Make your home feel warmer than it is
  • Force your AC to run longer and harder
  • Lead to mold and mildew growth
  • Increase wear and tear on system components
  • Shorten your AC unit’s lifespan

In short, too much moisture can turn your AC from a comfort tool into a stress case.

Signs Humidity Is Affecting Your AC

Not sure if humidity is the culprit? Watch for these telltale signs:

  • Sticky or clammy indoor air, even when the AC is running
  • Foggy windows (caused by indoor condensation)
  • Musty odors—a sign of mildew or mold
  • Inconsistent cooling or frequent cycling of your AC
  • Higher-than-usual energy bills

If you’re experiencing any of the above, it’s time to take action.

1. Use a Dehumidifier

The most direct way to combat high humidity is to install a whole-house dehumidifier that works in conjunction with your air conditioning system. These HVAC units are designed to:

  • Remove excess moisture before it circulates through your home
  • Improve comfort without having to overcool
  • Reduce mold risk in vents and ducts

If a whole-home system isn’t an option, room dehumidifiers can help in especially damp areas like basements or laundry rooms.

2. Keep Vents and Returns Clear

Blocked or restricted airflow can prevent your system from circulating air properly, allowing moisture to accumulate in specific areas of your home.

  • Make sure vents aren’t blocked by furniture, curtains, or clutter
  • Regularly dust and vacuum around vents and returns
  • Keep air filters clean and replace them every 1–3 months

When your AC operates more efficiently, it dehumidifies more effectively.

3. Set Your Thermostat to the Right Temperature

It’s tempting to crank the thermostat way down when it’s muggy, but lower isn’t always better. Setting your AC too low doesn’t necessarily solve the humidity problem—it just makes your system run inefficiently.

Instead:

  • Aim for a thermostat setting around 72–75°F during the summer
  • Consider using a smart thermostat that monitors indoor humidity
  • Use the “Auto” setting instead of “On” so your AC has time to drain excess condensation between cycles

4. Seal and Insulate Your Home

Humidity can sneak into your home through cracks, poorly sealed doors and windows, or insufficient insulation. Once it’s in, your AC has to work harder to keep up.

Take these steps to help seal out unwanted moisture:

  • Add weather stripping to windows and doors
  • Seal cracks around plumbing, electrical outlets, and attic spaces
  • Insulate your attic and crawl spaces
  • Use exhaust fans in high-humidity areas like bathrooms and kitchens

Minor improvements can make a big difference in how well your AC handles moisture.

5. Schedule Regular HVAC Maintenance

Routine AC maintenance is your best defense against long-term damage caused by humidity. During a professional service, a Charleston heating and cooling technician can:

  • Inspect and clean your condensate drain line
  • Check refrigerant levels and system pressure
  • Test thermostat accuracy and settings
  • Look for early signs of mold or mildew in ducts

Preventive maintenance helps identify minor issues before they become expensive repairs—and ensures your system operates at peak efficiency.

Stay Cool, Dry, and Comfortable with Our Expert Charleston HVAC Services

You don’t have to let South Carolina’s sticky air ruin your summer or your AC system. With a few proactive steps and help from your local experts, you can enjoy a cooler, drier, and healthier home throughout the entire season.

Do you need help managing your home’s humidity?Contact Prestige Heating & Air today for expert advice, customized solutions, and professional HVAC repair and preventative maintenance services. Our heating and air service technicians are here to keep your indoor comfort high and your humidity low, one service call at a time.