When to Use a Dehumidifier With Air Conditioner [And When Not To]

The ideal indoor humidity level is between 30 and 50 percent. In low-humidity areas, an air conditioning system effortlessly maintains that level year-round.  

However, regions such as the Southern United States experience extreme humidity, hindering an air conditioner’s ability to remove moisture from the air, and thus, cool properly.

In such cases, pairing a dehumidifier with an air conditioner is the most effective way to remove irritating moisture and maintain a comfortable room temperature.

Figuring out if your house requires both a dehumidifier and an air conditioner can be tricky. We’ll cover each scenario to best guide your decision. 

Humidity and Your Air Conditioner 

Have you ever wondered why it feels impossible to keep cool during humid months? 

When we sweat, the liquid evaporates into the air and reduces our body heat. Put simply, sweat cools us off but only if it can evaporate quickly. 

When there’s excess moisture in the air, sweat struggles to dissipate.

Therefore, our body temperature remains relatively high, resulting in discomfort. High-humidity levels affect how well an air conditioner cools similarly. 

Warm air holds more water vapor than cold air.

Hence the reason summertime is more humid than winter.

Because of this, an air conditioner may struggle to provide maximum comfort.

Although it’s removing warm air from a room, the humidity remains, meaning you’re still uncomfortable. 

This prompts many homeowners to crank down their HVAC system, causing it to work overtime and sometimes have faulty operation. 

Can an Air Conditioner Dehumidify? 

Somewhere along the line, you’ve probably heard an air conditioner doubles as a dehumidifier.

This statement isn’t false, but it’s not entirely true either. Let’s discuss why. 

Air conditioners cool warm air by running it over an evaporator coil with refrigerant running through it.

During the process, the evaporator coil also separates moisture from the air.

The coil drops the moisture off in a drain pan outside rather than returning it into the house.

The simple answer is yes, an air conditioner can dehumidify.

However, its primary purpose is to cool the air, and dehumidification is just a side effect of that process. T

herefore, a system’s dehumidifying capabilities become limited as temperatures and humidity increase. 

So, how can you know if your air conditioner is enough? Some common signs of a house being too humid include: 

  • Windows with fog or condensation 
  • Peeling or cracking paint 
  • Bathroom mildew 
  • Mold growth 
  • Dust mites 
  • Musty odors 
  • Excessive allergies or respiratory issues 

If you’ve run into any of these issues during high humidity, consider adding a dehumidifier to your home.

But, what if you don’t have an air conditioner? Is a dehumidifier alone enough to alleviate your discomfort? 

In many cases–yes! Let’s delve into when it is best or acceptable to use a dehumidifier without and with air conditioning. 

When to Use a Dehumidifier Without Air Conditioner 

A dehumidifier without the help of an air conditioning system is most efficient in areas with relatively low temperatures where air conditioners aren’t in demand.

Before, we can explain why you must understand the heat index.

The heat index takes the outdoor temperature and humidity level into account to determine what the temperature feels like to the human body.

For instance, if it’s 100 degrees Fahrenheit outside with a 50 percent humidity level, it will feel like approximately 118 degrees Fahrenheit. 

For this reason, it is generally safe to opt for a dehumidifier without an air conditioner in regions where temperatures rarely rise above 80 degrees.

Although a dehumidifier does not cool room temperature, it can reduce the heat index inside your house by removing moisture.

This approach maximizes comfort while saving you a significant amount of money as dehumidifiers are less expensive to run than air conditioners.  

When to Use a Dehumidifier With Your Air Conditioner 

Dehumidifiers pair well with air conditioning systems in regions that experience extreme temperatures and high humidity levels, such as Florida, Georgia, and Mississippi.

A high heat index can have dangerous effects on the human body, including fatigue, heat cramps, and even heat stroke.

As previously mentioned, the heat index takes both outdoor temperature and humidity into account.

So while a dehumidifier may reduce moisture in your home, it is not powerful enough to combat regularly high temperatures all alone.

However, an air conditioning system and a dehumidifier together can work better than independently.

The dehumidifier will remove moisture from the air while the air conditioner cools it down. Neither the dehumidifier nor the air conditioner overworks, preserving each component’s integrity.

Additionally, most HVAC units are compatible with whole-home dehumidifiers.

An expert can install the right one for your house size so you can forget about it until the winter rolls around and it’s time to switch it off.

A whole-house dehumidifier that works in tandem with an air conditioner is often the preferred method. It improves indoor air quality while reducing the power bill.

As the dehumidifier removes moisture, the indoor temperature feels cooler.

Therefore, many homeowners save some electricity by turning up their thermostats.

Benefits of a Dehumidifier 

1. Improves Health 

Excess moisture can have adverse effects on our health. Dust mites and mold thrive in humid environments. 

Both can cause allergic reactions and negatively affect people prone to allergies or respiratory illnesses. Luckily, neither can stay long in dehumidifier air. 

Dehumidifiers also make the air less heavy by removing moisture. This makes it easier for people with ailments, such as asthma or COPD to breathe. 

2. Lowers Energy Costs 

Whether you use a dehumidifier with an air conditioner or without one, your costs will be lower than that of an air conditioner alone. 

A large dehumidifier costs approximately 36 cents to run per 24 hours.

An averaged sized air conditioner costs more to operate per hour. This is proof that a dehumidifier in place of an HVAC system is significantly less expensive. 

As previously discussed, dehumidifiers also improve the heat index within a home.

Therefore, the air conditioner bears less of a heavy load. If your air conditioner sees at least an hour less of run-time per day because of a dehumidifier’s assistance, you will save money! 

3. Protects Your Home 

Dehumidifiers benefit more than your health and wallet–they also preserve your home! Excess moisture can cause a world of problems to your home’s structure. 

For instance, if water pipes aren’t insulated correctly, moisture breeds mold and mildew that can rot away at important structures, like doors and walls.

In a more serious scenario, inadequate ventilation in attics also promotes mold growth that can affect a home’s supporting frames.

Final Thoughts 

From improving indoor air quality to preserving the structural integrity of our home, dehumidifiers can drastically improve living conditions.

However, as you’ve likely learned, one size does not fit all.

Whether you use a dehumidifier with air conditioning or without depends on your living circumstances.

Where you reside, the size and layout of your home, and why you’re using the component should inform your decision.  

While this guide is enough to get you started, contact an expert so they can help you make the best choice for you and your home’s occupants.

About Roy Cohen

Roy Cohen has a burning passion for heating, cooling, and ventilation. He aims to help you save money on expensive repairs and bring you the best HVAC products. He has years of experience behind him in HVAC repair and garage maintenance.

You can find Roy at his LinkedIn or his email: [email protected]

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