Why Your House Feels Humid with the AC Running

Your air conditioner should do more than just cool the air—it should also remove humidity. So if your home feels sticky or damp even when the AC is running, something isn’t working as it should. Excess humidity not only makes your home uncomfortable but can also lead to mold growth, musty odors, and higher energy bills.

At Lakeshore Heating & Cooling, we help homeowners throughout Lake County identify the source of high indoor humidity and restore comfort with targeted HVAC solutions.

Common Reasons Your AC Isn’t Controlling Humidity

If your air conditioner is running but your home still feels muggy, sticky, or damp, you're not alone. Many Eastlake homeowners experience this problem—especially during Ohio’s humid summer months. While your AC is designed to cool and dehumidify the air, a variety of underlying issues can prevent it from doing its job properly. Below, we break down the most common causes and what you can do to fix them.

Your AC is the wrong size for your home

When it comes to air conditioning, bigger isn't always better—and smaller isn’t always more efficient. A system that’s too large for your home will cool the air quickly, but it shuts off before it has time to effectively remove humidity. This leads to short cycling, sticky indoor conditions, and added stress on your equipment. Conversely, an undersized AC system may run constantly, working overtime to reach your thermostat setting without ever fully dehumidifying the air.

Warning signs your AC may be improperly sized:

• • Rapid on/off cycles that fail to control humidity
  • Uneven temperatures throughout the house
  • Skyrocketing utility bills and premature system wear

At Lakeshore Heating & Cooling, we perform precise load calculations and offer expert HVAC installation services to ensure your new system is properly sized for your home, layout, and lifestyle.

The evaporator coil may be dirty or clogged

Your system’s evaporator coil is responsible for removing both heat and humidity from the air. Over time, this coil can become coated with dust, debris, or biological growth, especially if air filters aren’t changed regularly. A dirty coil restricts airflow, reduces efficiency, and traps moisture inside your unit—often leading to a musty smell and uncomfortable humidity.

Signs of a dirty or failing evaporator coil:

• • Weak or reduced airflow from vents
  • Ice forming on the indoor coil or refrigerant lines
  • Persistent humidity or mildew smell indoors

Our AC tune-up services include thorough coil cleaning to restore your system’s ability to dehumidify and cool your home properly. We also offer preventative maintenance plans to catch issues before they escalate.

Your system’s fan is running continuously

If your thermostat fan is set to “on” instead of “auto,” it will run continuously—even when the system isn’t actively cooling. This can cause your AC to recirculate humid air, making your home feel damp even when the temperature is technically at the set point. In some cases, this setting is unintentionally left on and goes unnoticed.

What to check:

• • Thermostat fan setting (switch from "on" to "auto")
  • Indoor humidity levels (ideal is 30–50%)
  • Duration of fan cycles between cooling

If you’re unsure how to adjust your system, we offer smart thermostat installation and programming services. Our technicians can help you control both temperature and humidity more efficiently with modern HVAC controls.

Poor airflow and duct issues

Your ductwork plays a critical role in how well your AC distributes cool, dry air. Leaky, uninsulated, or poorly designed ducts can cause your system to lose airflow and struggle to remove moisture, especially in rooms that are farther from the central unit. This leads to uneven comfort levels and longer, less efficient cooling cycles.

Common airflow and duct-related symptoms:

• • Hot or humid air in certain rooms (especially upstairs)
  • Noticeable dust buildup near vents or returns
  • Long AC run times with minimal comfort improvement

Our team provides duct inspections, sealing, and repairs that fix airflow issues and help your system perform the way it was designed to. Improving ductwork is one of the most effective ways to reduce indoor humidity and increase overall system efficiency.

High outdoor humidity and poor insulation

If your home isn’t well sealed, humid outdoor air can sneak in—making your AC work harder and leading to a consistently muggy indoor environment. Common culprits include leaky windows, unsealed doors, and inadequate insulation in attics or crawlspaces. This is especially common in older homes and during peak summer humidity in the Eastlake area.

How to reduce unwanted humidity infiltration:

• • Install weatherstripping on doors and windows
  • Add insulation to vulnerable areas (attic, garage, crawlspace)
  • Use bathroom and kitchen exhaust fans regularly

In cases where outdoor humidity overwhelms your AC’s dehumidification capacity, we offer HVAC-integrated dehumidifiers that remove moisture from the air without needing to overcool your space.

The system is aging or inefficient

Even a well-maintained AC system loses efficiency over time. If your unit is over 10–15 years old, chances are it’s struggling to remove moisture—even if it still cools the air. Outdated compressors, worn blower motors, and lower SEER ratings all contribute to poor humidity control and rising energy bills.

When to consider replacing your AC:

• • The system needs frequent or costly repairs
  • High humidity despite regular maintenance
  • Utility bills increasing without added usage
  • SEER rating below 13 (modern units often exceed 16–20 SEER)

We specialize in energy-efficient AC replacements that deliver modern comfort, better humidity control, and lower operating costs. Our HVAC experts will help you choose a system tailored to your home’s needs and budget, with financing options available.

Proudly Serving Lake County and Beyond

Lakeshore Heating & Cooling provides expert AC and humidity control services throughout:

• • Eastlake
  • Willoughby
  • Mentor
  • Painesville
  • Willowick
  • Wickliffe
  • Kirtland
  • Concord Township
  • Fairport Harbor
  • And nearby communities in Lake County

Schedule Your AC Humidity Check Today

Don’t live with that sticky, uncomfortable feeling. If your home feels humid while the AC is running, it’s time to let a professional take a look. Whether you need a quick repair, better insulation, or a new system altogether, we’ll guide you through the best options for your home and budget.

Call Lakeshore Heating & Cooling today or request a free estimate—we’re here to help you stay cool, dry, and comfortable all season long.