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8 Ways To Tell if a Dehumidifier Is Working Properly

Dehumidifier With Touch Panel, Humidity Indicator, Uv Lamp, Air Ionizer, Water Container Works At Home While People Relaxing With Cat.

A dehumidifier is an outstanding electrical device that improves our quality of life by keeping high humidity at bay. If the high humidity problem is not handled, it can cause mildew and mold growth, rotting of wood, musty odor, dampness, dust mites, respiratory, and other health issues, amongst others.

While a dehumidifier is easy to use, how can you tell if your dehumidifier is working correctly?


Many factors can cause the dehumidifier to stop working, such as a blocked filter, motor problems, frost on the coil, and the sensor. As such, to know if your dehumidifier is working correctly:

  • Check the water level.
  • Use a hygrometer.
  • Inspect the coils.
  • Feel the airflow.
  • Investigate the humidistat.
  • Watch out for leakage.
  • Inspect the indicators.
  • Listen to its sound.

Dehumidifiers operate in two simple ways─ by absorption and by refrigeration. The dehumidifier functions similarly to a vacuum cleaner, where the air is sucked into the unit and the moisture extracted from it.

This article explores how to test whether a dehumidifier is functioning. You will also learn some common problems that can arise that will affect the normal functioning of a dehumidifier.

8 Ways To Tell if a Dehumidifier Is Working Properly

Depending on the season and other moisture-related problems, the relative humidity indoors can range from less than 10% to over 90%. According to the Environmental Protection Agency, you must maintain indoor relative humidity below 60%. The ideal relative humidity should be between 30% and 50%.

With the right dehumidifier size (as they are classified by how much water vapor they remove from the air within 24 hours), you can cut down the relative humidity in your home. If you want to be sure the dehumidifier is working correctly, below are some tricks you can use to inspect the dehumidifier.

1. Check the Water Level

Woman Changing Water Container Of Dehumidifier At Home.

If the dehumidifier works as it should, it will remove excess moisture from the air. This moisture will be converted to liquid through refrigeration and accumulate in the water tank. If the water level rises after hours of using the dehumidifier, then the machine is working.

You can take this inspection one step further by checking the level at which the water rises to know the effectiveness of the machine. To check the machine’s state, mark the current water level, wait a few hours, and see how far the water rises past the line.

2. Use a Hygrometer

Man Monitoring Home Humidity Levels And Temperature With A Hygrometer Sensor And An App With Graphs On A Mobile Phone

Another way to know if a dehumidifier works is by using a hygrometer. A hygrometer is a handheld device that monitors the humidity level. With a hygrometer, take your home’s humidity level and then retake it after using the dehumidifier for a few hours.

If the machine is operational, the hydrometer’s humidity reading should decrease the second time. Note that the more humid this air is, the higher the difference you will see in the recording of the hygrometer.

3. Inspect the Coils

Using A Dehumidifier

Dehumidifiers have compressors in them that are temperature sensitive. As such, the coil ice when the temperature drops below a certain point. But when the coil is frozen, it stops the machine from collecting water from the air.

So, when you notice no change in moisture level in the demulsifier, disassemble the unit, remove the air filter, and inspect the coil. If you see any ice on the coil, know that is the reason your device is not working. It would be best if you defrosted the coil for the dehumidifier to work as it should.

4. Feel the Airflow

Woman With Her Cat Breathing Fresh Air At Home.

Another trick you can use to know if the dehumidifier is working as it should is to feel the airflow of the built-in fan. The fan draws air in and out of the machine. If the fan is not blowing air or rotating, your dehumidifier is not working.

Also, when you feel the outlet air, it should be warm because the air is reheated before returning to the room. If the air coming out is not hot, then there is something wrong somewhere with your dehumidifier.

5. Investigate the Humidistat

Woman Using A Dehumidifier In Her Apartment

Most modern dehumidifiers come with a humidistat that shuts off the machine when it reaches a target humidity level. The dehumidifier might be on but not working, not necessarily because something is faulty.

To be sure the dehumidifier is working, check the humidistat settings. If the humidistat is set at a level that is the current humidity level of the room, then that explains why your machine is not working.

6. Watch Out for Leakage

Portable Dehumidifier Collect Water From Air Inside Of Living Room

As we mentioned, dehumidifiers absorb moisture from the air converting it to water and storing it in a container. You should monitor the container, discarding the water when it is full. Most dehumidifiers have an anti-spill safety feature that stops the machine when it detects any leak.

Water leaking into the machine as it operates can cause electric shocks. So, always look at the level of the water puddle in and around the device. If it stops working due to water spills, clean it, allow it to dry, and then restart it to see if it will work as usual.

7. Inspect the Indicators

Dehumidifier With Touch Panel, Humidity Indicator, Uv Lamp, Air Ionizer, Water Container Works By Wet Window In Flat.

Like any other electrical device, dehumidifiers display their status with various indicators. You can use the indicator light to know how the machine functions at any given time. In some models, especially those with auto-shutdown, these indicators come on and off depending on the mode of operation.

So, if you are unsure whether the device is working, check the indicator. For example, some models have an indicator light to empty the water tank. So, if you turn on the machine, it will stop working because it can’t hold any more water.

8. Listen to Its Sound

Dehumidifier With Touch Panel, Humidity Indicator, Uv Lamp, Air Ionizer, Water Container Works At Home While Cat Sitting By It On Kitchen.

Finally, the sound the machine makes is another telltale way to know whether the device is working. Generally, dehumidifiers work with fans and compressors, which make some noise when operational.

So, if the machine is entirely slight, it is not working. But, at the same time, if the device is loud, it could mean something is faulty or wrong that needs your attention.


As you can see from this guide, it is pretty simple to check if your dehumidifier is working correctly. You can tell by simply feeling or listening to the airflow from the machine. Also, checking the water level is another helpful indicator. And if your dehumidifier is not working, you can easily disassemble it to diagnose the problem.

Frequently Asked Questions

How Long Do Dehumidifiers Last?

On average, dehumidifiers last around 5 years. But some premium quality dehumidifiers can last up to 10 years. And with good maintenance, you can extend its lifespan to 15 years or more.

How Long Should You Use a Dehumidifier?

Many experts recommend keeping a dehumidifier running for 12 hours a day. But with some modern dehumidifiers with auto on/off and auto-detection features, you don’t have to worry about the duration it works as it automatically adjusts as needed based on the condition of the environment it is operating.

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