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AC Is Cooling but Not Removing Humidity

an AC vent that is blowing out cool air but is not removing humidity

No one wants to be uncomfortable in their own home, especially when the air-conditioner seems to be working fine but something feels off. You have probably heard people living in desert climates say “It’s a dry heat.” But it’s still hot, and even worse than being hot in your house is sitting in a humid chill. What could be going on with your AC?

Usually, an air conditioner’s refrigerant draws in excess moisture from the indoor air. That vapor then condenses into water droplets. This drains into a pan under the unit’s evaporator coils and through a hose to your yard. If your AC isn’t pulling in that moisture, the humidity is just hanging around, which makes everything feel stuffy even if you are feeling a cool breeze. There are several reasons that your AC might not be dehumidifying. You can always contact a pro for AC problems, but there are some things you can check yourself.

Check Your Thermostat

Your air conditioner is meant to run when it needs to cool and then turn off. This allows the condensation that has built up to drain off. To do that, your thermostat needs to be set to a temperature that is comfortable to you and your family and to “auto.”

If the unit is set to “on” instead, then the AC fan is constantly running and not going through its intended cycle of dehumidifying, resting and draining try flipping the switch to auto and see if conditions improve. If things are still stifling and sticky, contact a licensed HVAC professional.

Slow the Fan Speed

You might think faster is better when you are trying to pull excess moisture out of your house. A lot of AC systems are set to move air quickly, but if you are looking to dehumidify you will want to reduce the speed.

When your system is moving air quickly, it will take the heat out and hit your preferred temperature. But it won’t necessarily draw out that moisture that can reduce your comfort. When you set the speed lower, the lower airflow lets your unit’s indoor coil get colder. That pulls out more humidity. Ask your licensed HVAC professional about making this switch. They can help advise you on whether a variable speed AC would help maximize the moisture control in your home.

Refrigerant Issue

Take stock of any other problems you might notice with your AC. Maybe you are hearing unusual AC noises. In addition to a noticeable increase in humidity, you might also feel warm air pouring out of your vents. Or maybe you are noticing that your cooling unit is working extra hard and not cooling as well as it normally does. You may have a leak in a refrigerant line.

Refrigerant is how your AC pulls the heat and moisture from the inside of your house and tosses it outside. Normal wear and tear can cause cracks in the lines that run the refrigerant throughout your air conditioner. If you suspect this is the case, your best bet is to call in a licensed professional who can make this AC repair, recharge your system and get you back to comfort.

Time to Vent

It’s not unusual for the ductwork connected to your air conditioner to be a bit leaky. In fact, most homes lose almost a third of the cooled air flowing from the AC to such leaks. Is your energy bill suddenly rocketing sky high? Does all the dusting in the world make no difference in the cleanliness around your rooms? Depending on where your ductwork lives, these leaks can be a reason for more than just extra moisture to be floating around.

Some homes have HVAC ductwork in the attic, down in the basement or in an uninsulated crawl space. If you have leaky ducts, you are going to be pulling dirt and grime through the ductwork and into your home, cutting into the dehumidifying process. It also reduces the quality of the very air that you are breathing. Call an HVAC pro who knows exactly where and what to look for to find and fix the problem.

an AC vent

How to Clean AC Coils

Coils are an integral part of any air conditioning system. Without them, your unit can’t do its two main jobs: cooling and dehumidifying. The moisture from the air condenses on the coils as they cool. Then that water that was pulled from the air in your home drains away, leaving your home feeling much more comfortable.

Because the coils draw moisture, they can be a bit damp most of the time, attracting dust and dirt and even pollen. These things can pile up and lower the effectiveness of your entire air conditioning system. You will also see a buildup of gunk if your AC’s air filter is clogged and in need of changing. It doesn’t take long for all these little particles to cause big trouble.

Dirty coils can keep your air unit from running at peak efficiency, costing you both comfort and cash. You might be paying 40% more for your AC bill just due to coils that need cleaning. Ice can build up as well, freezing your system and potentially causing more damage.

The coils and the rest of the AC system should be cleaned at least once a year, ideally as part of an annual maintenance routine. As tempting as it might be to get in there and clean things out yourself with compressed air or a good brush, it can easily be more trouble than it’s worth. A licensed HVAC professional has the experience needed to clean all the most important parts and check to make sure everything is in good working order. In addition, they can catch any AC repairs before they become larger, more expensive problems.

a gray home with brick

Is Your AC Unit Too Big for Your House?

Everyone wants to be comfortable inside their home, so having no shortage of cool air on tap might be a tempting idea. But, going big often isn’t the best plan. If you are putting in a new system, talk to a licensed pro to get tips on what size and style of air conditioner will fit your needs.

What about if your home came with a system that might be too much? How can you know? One simple clue is how quickly the AC turns on and off. If it takes 5 or 10 minutes for the air conditioner to cool your home to your desired temperature, that’s a sign that the unit is too powerful for your home. That might sound great, but a stop-and-start system can wear out quicker and also push up your energy bills.

Another side effect of a system that cycles too quickly is a reduction in its ability to dehumidify. The humidity level in your home should typically sit between around 30% and 50%. The only way it can maintain that kind of comfort is by running normal on-off cycles. This won’t happen if the system is too big. Again, this can mean discomfort physically and financially.

HVAC professionals know that before you install a system, you need to run a “cooling load calculation.” This formula includes information like your home’s square footage; how many rooms, windows and doors it has; the climate where you live; and many other factors. If your home is too humid and you suspect an overly large air conditioning system is the culprit, contact a licensed expert to take a look. If your home would be better served by a smaller AC system, your professional can walk you through your options for replacing your AC and installing a new system.

ABC Can Maintain Your AC

When your AC system isn’t working properly, it’s the best bet to call in a licensed professional for AC diagnosis and repair. Our licensed pros can maintain your system and notify you of any potential problems before they become bigger headaches.

Tom Riggs

Tom Riggs is the Division Manager for Mechanical Services, overseeing sales and operations for HVAC, Plumbing, Electrical, Appliance Repair and Water Quality for all ABC Austin branches. He joined ABC in 2014. Before ABC, he was an HVAC Service Technician, HVAC Comfort Advisor/Sales and Operations Manager. Tom attended Universal Technical Institute. He's an avid outdoorsman and enjoys country living with his wife and two sons.

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