Why Is My Dehumidifier Blowing Hot Air

Last updated on May 12, 2022 FEATURED
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Dehumidifiers work by maintaining comfortable indoor air quality. However, it might be frightening to see your unit working in an uncommon way. For instance, you might have noticed your unit is blowing hot air. And therefore, you must be asking yourself why is my dehumidifier blowing hot air.

A dehumidifier blowing hot air is sometimes normal due to its working mechanism. However, if the air is so hot, then there could be a mechanical malfunction. So, if you are experiencing this problem, do not worry, we can help you solve it.

In this article, we discuss how dehumidifiers work, and what could make them blow hot air.

How Dehumidifiers Work

Dehumidifiers work in two ways depending on the model. Most of them follow a refrigeration process or absorption process. Let us discuss them in detail.

  • Refrigeration

Image showing how dehumidifier using a refrigeration process work
How Refrigeration dehumidifiers work

Under the refrigeration process, dehumidifiers remove moisture following a similar process to a refrigerator. They commonly collect moisture through a grille. These dehumidifiers use electric fans to pull air inwards. The pulled air passes over freezing pipes, which makes it cool.

When the warm air cools down, it starts losing its moisture.  The lost moisture turns into liquid and drops off into the dehumidifier tank. Thereafter, the moisture-free air moves over a hot compressor unit. This warms the air back to its original temperature.

Then the dehumidifier blows the warm air free of moisture back into circulation through the grille. This process continues until the unit is switched off or when the bucket/tank is full.

  • Absorption or Adsorption

Image showing absorption/adsorption dehumidifier
How Absorption dehumidifier Work

This process can be called desiccant dehumidification. Under this process, moist air is pulled into the dehumidifier through a rotating silica gel rotor. Basically, a desiccant material pulls moisture to its surface, removing it from the air.

The rotor splits the air into two. The first portion of the air is pushed into circulation as dry air and the other one is used to regenerate the rotor. As the air moves out, it is exposed to a heater to make it warm again. By slowly maintaining the rotation of the rotor, the dehumidification process is maintained.

Why Is My Dehumidifier Blowing Hot Air

As shown above, in the refrigeration process the moist-free air is heated. After removing moisture from the air, the moist-free air passes over a hot compressor, which warms it again. This means the air blown into circulation is hot. 

 However, this air should not be too hot. Generally, this air should not be as hot as that coming from the furnace that warms your house. Under normal circumstances, dehumidifiers should blow air that is around 3-5 degrees Fahrenheit warmer than room temperature.

If your dehumidifier is generating hot air of more than 5 degrees Fahrenheit, then there is reason to worry. Let’s see some of the possible reasons why your unit is blowing hotter air.

Possible Reasons Why Dehumidifiers May Produce Hotter Air

  • Dirty Evaporator Coil

One of the primary reasons why your dehumidifier blows hotter air is dirty evaporator coils. As shown earlier, dehumidifiers mainly remove moisture from the air by cooling the air below its dew point. Given that cold air cannot hold moisture, moisture will start condensing.

After losing moisture, the cool air moves over a hot condenser coil and gets heated. In this case, if the evaporator coil is dirty, it will not cool the air to the required level. So, as this air passes through the condenser coil, it can be heated to a much higher level than normal. Therefore, if your dehumidifier is blowing much hotter air, consider cleaning or replacing the evaporator coil.

  • Broken Components

If your dehumidifier has some malfunctioning or broken components, it may start blowing hotter air. These broken components can affect the performance of a dehumidifier, thus making it blow hot air. So, you may have to contact your service provider or technician for assistance.

  • Full Tank/Bucket

Normally, humidifiers cool down the air to remove moisture, which drips into the water tank. When the water tank is full, some dehumidifiers can automatically shut off. However, if yours does not shut off automatically, then it may start blowing hot air.  

This is because when the water tank is full, the dehumidifier continues running, and the moist air will not be cooled. As a result, it will be heated before losing its original heat. This will make the dehumidifier blow hotter air.

To avoid such circumstances, always turn off the dehumidifier when the tank is full. Also, you can empty the water tank before it gets full.

Can Dehumidifier Make The Air Too Dry

Yes, dehumidifiers can make the air too dry. Dehumidifiers are supposed to improve indoor air quality by removing excess moisture. However, it is unfortunate that some dehumidifiers make the air in a home so dry. This may spark various health complications such as nose bleeding, dry skin, itching eyes, irritated airways, and others.

What you should note is that the warm or hot air coming from a dehumidifier is not responsible for making the air dry. Dehumidifiers can only make the air too dry through over-dehumidification.

These units are supposed to maintain a specific range of humidity. In other words, it should maintain a maximum humidity range i.e 50%. So, a good dehumidifier should pause when humidity is at 50% or less. It may resume automatically or when switched on manually when humidity increases.

In case, it switches off automatically or is turned off manually when humidity is at the required level, it will continue dehumidifying. Certainly, this can make the air dry.

How To Prevent Dehumidifiers From Making The Air Dry

  • Use Dehumidifiers With Built-in Humidistat

Humidistat can monitor the current indoor humidity and adjust the fan speed automatically. When humidity is high, the humidistat sets the dehumidifier to run at maximum speed. Similarly, as humidity reaches the ideal range, the dehumidifier pauses. This makes it impossible for the dehumidifier to dry out the air.

However, you need to preset your ideal humidity range so that the unit adjusts accordingly.

  • Use Hygrometer Device

In case you have a dehumidifier without a built-in humidistat, you can get a hygrometer. The device can help monitor your humidity levels as the dehumidifier is running. So, you need to keep checking on the device. If you find humidity is within your ideal range, then you can switch off the dehumidifier. Likewise, when the humidity level is above the maximum value, you can restart the unit again.

Are There Risks When A Dehumidifier Makes The Air Dry

Yes, there are health risks when you inhale dry air. Some of the problems you may experience due to dry air include

  • triggering an asthma attack
  • Irritating the respiratory system
  • sore throat
  • Dry skin and dermatitis
  • Nosebleeds
  • Eye irritation


Dehumidifiers blowing hot air is normal. However, it should not be as hot as that of a furnace or that from boiling water. If your dehumidifier is blowing air hotter than 90 degrees Fahrenheit, then your unit is not functioning well.

This might be a problem with the evaporative coil, broken components, or full water tank. The good news is that these problems can be assessed and addressed by yourself as highlighted above.

The hot air coming from a dehumidifier does not dry out the air as many anticipate. However, it is the problem of over-dehumidification that can make the air dry. Therefore, endeavor to monitor your unit as it is running to avoid drying air. 

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