Dehumidifier on AC Unit – Is It Effective at Maintaining a Mold-Free Home

Tackling ever-lurking mold growth in humid regions, like Florida, is indeed a daunting challenge. It not only wreaks havoc on property, causing significant damage, but also poses some serious risks to your health.

This article will focus on the use of an air conditioning unit in dehumidifier mode as a potential solution to maintain a mold-free living environment. We are going to explore its effectiveness, and compare it with a dedicated electric dehumidifier.

So let's jump right in!

Maintaining a Mold-free Home: Why It Matters

Fungi, more commonly known as mold, takes root in your home leading to various health problems, ranging from pesky respiratory problems, allergies to infections. 

Moreover, these uninvited guests not only cause structural damage your home but also burn a significant hole in your pocket due to the ensuing costly repair work. To prevent these issues, take control of indoor humidity levels is very important.

An indoor atmosphere with high humidity creates an ideal environment for mold to grow. Effective control of mold, mildew, and other allergens can be achieved by regulating indoor humidity between 30% to 50%. This scenario is where the dehumidifier mode of an AC comes into play.

This mode operates by extracting excess moisture in the air, while cooling the air down. The process helps decrease the amount of moisture in your room, thus making the environment less favorable for mold and mildew growth.

It's crucial, though, to comprehend that the functionality and success of this dehumidifier mode also depends on the capacity of your AC unit and the dimensions of your room.

What is a Dehumidifier Mode on an AC Unit?

Also known as 'dry mode,' dehumidifier mode is a specialized feature incorporated into many AC units. Its prime focus is on reducing the moisture content in the room where it services. 

While the fundamental purpose of an AC is to cool the air down, dehumidifier mode sets its sights on specifically removing excess humidity, without dramatically impacting the room temperature.

This function is especially useful for locations where elevated humidity can lead to discomfort and likely harm to your belongings and properties.

How Does Dehumidifier Mode Work on an Air Conditioner?

When your AC is set to dehumidifier mode, it starts by drawing in the room's humid air. As this air passes through the evaporator coil, the temperature drops causing the moisture in the air to condense upon the cold surface of the evaporator.

This process effectively extracts the moisture from the room's atmosphere, leaving behind drier air. This dehumidified air is then circulated back into the room -- simplicity at its best!

Rather than mimicking the standard cooling mode, the dehumidifier mode employs both compressor and evaporator coil to remove humidity without excessively cooling the room.

In dehumidifier mode, the compressor operates at reduced speed and cycles on and off as needed to avoid unnecessary cooling. This decrease in relative humidity generates a sensation of coolness, even if the room's actual temperature remains unchanged.

AC Dry Mode vs Dehumidifier: Understanding the Difference and Benefits

The dry mode of the air conditioner focuses on dehumidifying the air, whereas a dedicated dehumidifier seeks to strip the excess moisture from the air without inducing a cooling effect.

With that said, if you want to reduce humidity in your home in cold months, an electric dehumidifier is your best bet!

Understandably, the benefits and distinctions between both the dehumidifier mode in AC and a dedicated dehumidifier might seem confusing.

Here's some key differences:

AC Dry mode

  • Optimizes indoor atmosphere by keeping humidity in check
  • Promises energy efficiency through reduced energy consumption compared to regular cooling mode
  • Significant check in favor of preventing mold and mildew that grow in damp environment.
  • The go-to option for areas with moderate levels of humidity

Standalone dehumidifier

  • Operates independently to maintain optimal humidity, but without inducing a cooling effect
  • Specially designed for dehumidification
  • Perfect for spaces such as basements or laundry rooms where humidity and dampness is a concern.

Here's a comparison of using the dehumidifier mode on an air conditioner versus using a dedicated dehumidifier:


Dry Mode in AC

Dedicated Dehumidifier

Moisture Removal



Coverage Area

Limited to the room being cooled

Cooling Ability



Allergen Control



Energy Efficiency

Energy consumption based on cooling capacity

Energy consumption based on dehumidification capacity

The duality of effectively reducing humidity via either the air conditioner's dehumidifier mode or a dedicated dehumidifier is not in dispute.

However, there's an element of practicality tied with the AC's dehumidifier mode—it provides a 2-in-1 service by cooling and lowering moisture levels simultaneously.

Admittedly, any expectations of this mode performing just as potently as a dedicated dehumidifier should be tempered especially in larger rooms or spaces that grapple with chronic moisture problems.

In situations demanding optimal results, the combination of your AC with a standalone dehumidifier, tailored to the specific dimensions and needs of your dwelling, can be your best bet.

How to Tell If Your AC Has a Dehumidifier Mode

Wondering whether your AC is equipped with a dehumidifier mode?

It's quite simple: find a dry mode option or a symbol of a water droplet on your air conditioner remote control, indicating this feature. A press of the ‘mode’ button cycles through the modes until you spot your desired dehumidifier function.

If uncertainty clouds your judgement, the manufacturer's guide or a qualified HVAC professional can offer necessary guidance.

To sum it all, AC's dehumidifier mode can effectively reduce excess humidity and bring a comfortable and healthier living ecosystem—a boon indeed, particularly in high-humidity regions or during damp seasons.

The Limitations of the Dehumidifier Mode on AC Units

Despite its ability to reduce moisture and make indoor living spaces more comfortable, the dehumidifier setting on air conditioning units has its limits. Acknowledging these restrictions is crucial to effectively prevent mold in your home.

Here are some factors to consider:

  • Space size: The efficacy of the AC dry mode can vary depending on your space size. Greater square footage may require additional dehumidifiers or other methods to effectively lower the humidity.
  • Environmental conditions: The dehumidifier setting of an AC may not perform optimally in areas with exceptionally high moisture content. In such conditions, extra precautions like dedicated dehumidifiers or moisture-absorbing materials might be essential to reduce moisture and prevent mold development.
  • Maintenance and cleaning: Regular maintenance and cleaning of your air conditioner is key for the superior performance of the dehumidifying feature. This includes replacing or cleansing filters, inspecting for blockages, and proper drainage of the accumulated moisture.
  • Insulation and ventilation: Appropriate insulation and ventilation are key to preserving a mold-free home. Inadequate insulation or improper ventilation can lead to moisture build-up, thereby increasing the challenge for the AC dry mode to reduce humidity effectively.
  • Mold prevention measures: Although the dehumidifier mode on an AC helps manage moisture, implementing additional steps to prevent mold is essential. This might include regular inspections, addressing potential water leaks or moisture interference points, and maintaining appropriate ventilation in areas prone to moisture buildup.

Ensuring these aspects are duly considered while augmenting with additional measures as needed, you can effectively maintain a house free from mold, creating a healthier living space.

It is crucial to routinely check humidity levels, tackling any moisture-related problems swiftly to prevent mold growth and protect your belongings and properties.

People Also Ask

Does Running a Dehumidifier Help the Air Conditioner?

Running a dehumidifier along with an air conditioner enhances the air conditioner's efficiency in maintaining a mold-free home. While the prime role of an air conditioner is to cool the air, it also has the ability to dehumidify.

Nonetheless, an air conditioner may not be as effective in moisture extraction compared to a dedicated dehumidifier. By running a dehumidifier parallelly with the air conditioner, you can ensure efficient removal of residual moisture from the air, minimizing the possibility of mold development.

Is It Cheaper to Run the AC or a Dehumidifier?

Regarding power consumption, primarily, the operation of a dehumidifier tends to be more economical compared to an air conditioner. However, bear in mind that both appliance’s energy usage depends on their capabilities and running times.

On average, an air conditioner drains more power than a dehumidifier. Running a dehumidifier alongside an air conditioner could, in fact, reduce the load and energy consumption of the air conditioner, as the dehumidifier reduces extra moisture from the air, paving the way for long-term cost-effectiveness.

Please note that the effectiveness of dehumidification through an air conditioner depends on the specific model and its features related to dehumidifying. Some air conditioners are equipped with a distinct dehumidifying function or feature enabling the control of the dehumidification process. Ensure to check the specifications and features of your air conditioner to determine its dehumidifying capabilities.

Why is My AC Producing So Much Humidity Instead of Reducing It?

In that case, you might have an issue within the cooling coils or drainage network, encouraging the accumulation of moisture and subsequently unsettling the ideal dehumidification process.

Dirt accumulation and debris clogged in the AC unit's air filter might be the cause, as well.

Final Verdict

In closing, it's vital that a mold-free home is prioritized for your family’s health and well-being. Both an AC in dry mode and a dehumidifier are formidable allies in the regulating humidity in the battle against mold growth.

While the AC dry mode focuses on humidity reduction without fundamentally cooling the environment, a dehumidifier is specially designed to remove humidity from the air. The verdict between employing an AC in dry mode and a dedicated dehumidifier depends on your specific needs, budget, and the local climate.

In a majority of scenarios, a dedicated dehumidifier seems to outperform an AC unit's dry mode. Consider factors like room dimensions, existing humidity levels, and preferred level of control to identify the prime solution for achieving and maintaining a healthy, mold-free living environment.

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My name is Justin Williams. I am the founder and blogger at (read more about us). I was an allergy sufferer and that is also the reason why I began my trek to finding the best dehumidifier for my own personal health issues. All of the dehumidifier top picks on the site were put through their paces by Lance Perez - our dehumidifier researcher. He put each one through a series of tests to see how well they performed. Then, our editorial team compiled the insights into articles and published them.

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