image of an indoor tropical plant with condensation on the windows

As the residents of Hawaii can readily attest, island life can quickly become miserable when your AC stops functioning correctly. More specifically, it’s tough when your AC begins to make your home feel humid and muggy rather than cool and refreshing. You may be asking, “Why is my house so humid with the AC on?” You’ve come to the right place for an answer!

At Island Comfort, we understand how awful it can be when your AC stops working. So we’ve provided some explanations for why your AC isn’t working, possible repair tips, and factors to decide when you should call a professional.

House is Humid With AC On: Why is it Happening?

There are several explanations for why your HVAC system is causing your home’s humidity levels to rise. The most common humidity cause is the thermostat being on the wrong setting. If your thermostat is on your desired setting, yet the air from your unit remains humid, another issue could be present. 

Humid air can also result from dust and debris within your HVAC unit. When grime builds up inside the machine, air cannot properly flow, resulting in the hot, humid air. Let’s explore these common issues along with several other contributing factors.

Frozen Evaporator Coils

If you find that your HVAC unit is free from debris buildup, there could be a problem with internal components, such as evaporator coils. The evaporator coils are responsible for cooling the air before expulsion from the vents. Over time, the coils can freeze and cease to function correctly, resulting in hot air.

AC Lifespan

Finally, once you’ve checked for the previous potential causes and your air is still humid, it may be that your system is simply nearing the end of its life. Typically, an HVAC system can function for up to 20 years. If your system is approaching this age and experiencing these problems, it’s probably time to start looking for a new HVAC. 

Reasons for indoor humidity infographic

House Feels Humid With AC Running: Possible Solutions

Even though your AC is causing humid air in your home, there are possible solutions to resolve the problem. The following are several things to consider when conducting AC repairs or reaching out to a technician for professional servicing:

Thermostat Issues

Before calling your HVAC technician, homeowners can first determine whether the thermostat is causing high indoor humidity levels. Start by checking if your thermostat is set to “auto” rather than “on.” 

When your AC is set to “auto,” it will continuously cool while acting as a dehumidifier for your home. Whereas, when you set your AC to “on,” the system will continue to run around the clock without going through dehumidification cycles. Of course, the result will be the production of humid air instead of cool, refreshing, and dehumidified air.

Build Up of Debris

One of the most common causes of high humidity levels is the buildup of dirt and other debris within the AC unit’s air filter. If the air filters are dirty and covered in debris, your AC system will not function properly. 

As dirt and dust build up within the air filters, your AC cannot disperse hot air through the outdoor vents, leading to an accumulation of hot, muggy air. Therefore, it’s crucial to ensure that your HVAC system has clean filters to cool air and avoid high levels of humidity properly.

Improper System Size for Your Home

Many homeowners think that bigger is better when it comes to an air conditioning system. However, this isn’t always the case. Larger units can cause increased indoor humidity in smaller homes by cooling the house too quickly and not allowing for complete cycles. On the other hand, if your AC unit is too small for your home, it could lack the power required to dehumidify the air in larger rooms, resulting in hot, muggy air. To avoid purchasing the wrong sized AC and experiencing humid air, discuss your home’s exact measurements with your HVAC company.

Malfunctioning Evaporator Coils

As a result of either prolonged usage or debris build-up, evaporator coils can begin to malfunction and lead to excess moisture. Once moisture settles on the coils, they may freeze, hindering your AC from adequately extracting heat and humidity from the air in your home. If you believe that your AC is experiencing this issue, immediately consult your HVAC technician to avoid lasting damage to your system.

Your System is Too Old

In some cases, you may have to consider that the age of your AC may be the cause of the high levels of humidity in your home. While this is certainly not what you want to hear, older systems begin to malfunction after years of operating. 

You can expect your HVAC system to last at least 15 years before showing any significant wear and tear. Once it reaches a ripe age, the presence of hot, humid air coming from the vents can signify that it’s going out of order. You’ll most likely have to replace the entire system in this instance. On the bright side, your HVAC technician will be able to walk you through the process and find a suitable replacement.

High Humidity Levels

If you’re experiencing hot and humid air even though your AC is running, the problem could be as simple as increased outdoor humidity levels. Of course, if it’s the middle of winter, this won’t be a likely explanation for your system’s inability to regulate humid air. 

However, your AC system can’t keep up when the air is sweltering with excess humidity (as it tends to do in places like Hawaii and Florida). To offset this issue, make sure that all windows and doors are closed in your home. Additionally, if you live in an area that experiences hot temperatures throughout the year, you may even have to consider updating your AC to a more robust system. 

Before deciding how to proceed, always discuss your options with your HVAC maintenance company.

When to Seek Professional Servicing

After checking the thermostat, cleaning the air ducts of debris, and restarting the system, it’s time to call a professional servicing team to help get to the root of the problem. 

It’s important to remember that anytime there’s an electrical issue, such as loss of power or loud noises coming from the inside of the unit, you must call a professional quickly.

Island Comfort Air Conditioner Maintenance Services

An improperly functioning HVAC system in Hawaii is no fun for anyone. Therefore, if your HVAC system is causing humid air or poor indoor air quality, we want to serve you and restore your comfort level.

In addition to our HVAC maintenance services, we also provide a range of different air conditioning products and services. So whether you need a simple window unit or an entirely new HVAC system, we’re the company you can trust. For more information about our services, reach out to us on our website today.