High Humidity in Your Home This Summer? Your AC Might Be the Problem

We have all been there. It is the middle of July in Ontario, and the air outside feels like a warm, wet blanket. Whether you are living in the busy suburbs of Markham, Richmond Hill, Scarborough, Vaughan, Mississauga, or Newmarket, or you are based in Durham, Ottawa, Waterloo, London, Barrie, Hamilton, Burlington, or Kanata, summer is synonymous with heavy humidity.

But what happens when you step inside, expect a blast of dry, crisp relief, and instead get hit with a sticky, damp chill? Your thermostat says it is 21 degrees, but your skin feels clammy and uncomfortable.

If your home feels like a tropical rainforest even with the air conditioning running, you are not imagining things. Your AC is likely struggling with a hidden problem.

How Your AC Is Supposed to Fight Humidity

Most people think air conditioners only cool the air. In reality, controlling moisture is just as important as lowering the temperature.

Here is how the process works in a healthy system:

• Warm, humid air from your home gets pulled into the system and passes over freezing-cold evaporator coils.
• As the warm air hits the cold metal, moisture condenses out of the air—just like condensation forming on a cold can of pop on a hot day.
• The liquid water drips into a drain pan and flows safely outside your home through a condensate line.
• The newly dried, cooled air is blown back into your rooms.

For peak comfort, your indoor humidity should stay between 30% and 50%. Once that number climbs past 60%, the air gets saturated, sweat cannot evaporate from your skin, and your home starts to feel sticky and damp.

6 Reasons Your AC Is Leaving Your Home Sticky

When your cooling system fails to pull moisture from the air, it is usually due to one of these common issues:

• Your Air Conditioner Is Too Big: It sounds backward, but a larger system is not always better. If your builder or installer put in an oversized AC, it will cool your home down incredibly fast and then shut off. This is called short cycling. Because the system only runs in quick, ten-minute bursts, it never stays on long enough to actually condense and drain the humidity. You get cold air, but all the moisture stays trapped inside.
• The Thermostat Fan is Set to "On": Take a look at your thermostat. If the fan setting is switched to "On" instead of "Auto," your blower fan will run non-stop. When the cooling cycle ends, the compressor turns off, but the fan keeps blowing air over the wet coils. This pushes the evaporated moisture right back into your living spaces.
• Clogged Air Filters: Dust, pet hair, and dirt block airflow. When air cannot move freely over your evaporator coils, the coils get too cold and can freeze solid. A frozen coil cannot pull moisture out of the air, leaving you with weak, damp airflow.
• Low Refrigerant Levels: Refrigerant is the lifeblood of your AC. If your system has a tiny pinhole leak, the refrigerant levels drop. This prevents the evaporator coils from getting cold enough to squeeze water vapor out of the air.
• Ductwork Leaks: Over time, ducts can crack or pull apart. If you have leaks in your ductwork, your system can pull in hot, humid air from your attic or basement and blow it straight into your bedrooms.
• A Blocked Condensate Drain: Dust and algae can clog the narrow drain pipe that carries water out of your home. If the water cannot drain, it pools in the pan and re-evaporates back into your home’s air.

The Hidden Dangers of Excess Indoor Moisture

Ignoring a damp home is about more than just feeling uncomfortable. Consistent high humidity is bad for your health and your property:

• Mold and Mildew Growth: Damp air creates a breeding ground for mold spores, mildew, and dust mites in your carpets, drywall, and air ducts.
• Respiratory Issues: Airborne spores and damp conditions can trigger severe allergies, wheezing, and asthma attacks, especially in kids and seniors.
• Property Damage: Excess moisture warps hardwood floors, swells wooden doors and cabinets, peels wallpaper, and ruins paint.
• Skyrocketing Energy Bills: When the air feels sticky, you are more likely to turn the thermostat down even lower. This forces your AC to run longer, raising your electric bills without actually fixing the humidity.

Easy Steps to Dry Out Your Home

You can take action to bring your indoor humidity back under control:

• Switch the fan setting to "Auto" so moisture has time to drain between cooling cycles.
• Change your air filters every 1 to 3 months to keep the air flowing smoothly.
• Seal up drafts around your windows and doors with caulk or weatherstripping to keep outdoor humidity outside.
• Run your exhaust fans in the kitchen when cooking and in the bathroom during and after showers to vent moisture directly outdoors.
• Have your ducts inspected to make sure they are not pulling in hot attic air.
• Consider a variable-speed air conditioner or heat pump that runs at lower, continuous speeds to constantly pull moisture from the air.
• Install a whole-home dehumidifier that integrates with your existing HVAC system to manage heavy humidity automatically.

Let Constant Home Comfort Bring Back the Chill

Note: Rebate amounts and eligibility can change over time. For the latest incentives, visit our Promotion page.

If you have tried the basics and your home still feels muggy, it is time to call in the professionals.

Constant Home Comfort has spent over a decade helping homeowners across Southern and Eastern Ontario stay cool, dry, and comfortable. Whether you need emergency repairs, seasonal coil cleaning, or a brand-new system upgrade, our fully licensed and insured technicians have you covered.

Why Ontario homeowners trust us:

• Award-Winning Service: We are a proud winner of the prestigious Lennox Centurion Award, placing us in the top 2% of Lennox dealers in North America.
• Big Brands, Better Prices: We source directly from major brands like Lennox, Goodman, KeepRite, and Gree, and pass those wholesale savings directly to you.
• We Handle the Rebates: Save up to $7,500 on qualifying high-efficiency heat pump upgrades and insulation improvements through programs like the HomeEnergySaver rebate. We file all the paperwork for you.
• Flexible Payment Options: Get a brand-new central air conditioner installed starting from $1,599 with rebates, or a high-efficiency furnace from $799 with rebates. We also offer flexible $0-down, 0% interest financing for 12 months on approved credit, so you do not have to pay until next year!

Do not spend another sticky night tossing and turning. Call Constant Home Comfort today at 1-888-675-5907 for a free quote, or visit our main office at 2-201 Don Park Road, Markham, ON L3R 1C2.