Should a Dehumidifier Run Constantly? 5 Main Reasons that Cause This

What do you do if your dehumidifier will not shut off? It can be a spot of bother, for sure!

Unless there has been flooding, and you are trying to dry out damp walls, the dehumidifier should not run constantly.  Besides, if it is a cheaper unit, running it constantly can cause overheating.

The good thing is that this is not a question that you need to sweat too much about, since your Frigidaire dehumidifier will have a built-in humidity sensor.

Thus, when it lowers the humidity level appropriately, it will switch off automatically. Again, if the humidity level rises above the recommended 50% level, the built-in humidistat senses the same, and the dehumidifier restarts automatically.

Because a dehumidifier might fail to work correctly at times, do not panic if you see that yours is running all the time.

As we saw in the article on why the Midea dehumidifier does not collect water, many things could go wrong with your unit.

Keep reading to see more information about the running state of a dehumidifier.

Why is my dehumidifier not shutting off?

There are many reasons why a dehumidifier would run all the time. If yours does that, you can be sure something is wrong. You would need to fix it.

As always, in this blog, I recommend that when your dehumidifier or humidifier is not working correctly, start with the simplest checks and fixes. If they don’t work, move on to more complex ones.

1. The humidistat is failing

The work of the built-in humidistat is to sense changes in the humidity level in your home. If the humidity rises above the set level, the humidistat sends a signal to the circuit board, and the dehumidifier starts automatically.

Once the humidity level drops below the set threshold, the humidistat sends a signal to the circuit board, and the dehumidifier shuts down.

With that information in mind, you can see why the dehumidifier fails to work if the humidistat is not working correctly. It sends the wrong information or doesn’t send any at all.

Solution: If the humidifier is under warranty, you can contact the manufacturer so that they can direct you to the nearest repair center.

If the warranty is expired, you can order a replacement humidistat from the manufacturer or from online marketplaces.

2. The dehumidifier is too small

Dehumidifier and humidifiers have a space rating for a reason. Thus, if it is too big, it will shut off too fast.

If you use a small dehumidifier for 2 x 2 feet in a 10 x 10 space, it is not going to work properly. It will not lower the humidity in the appropriate time.

Therefore, a unit that is too small for the space you want to use it in will run non-stop, since it can only stop when it lowers the humidity to the desired level.

Read the description of the dehumidifier before buying it. That way, if you buy a dehumidifier for a 4 x 4 tent, only use it in such a space.

Besides the dehumidifier running continuously due to its small size, you will also need to empty the bucket too often.

Solution: Measure the size of the room where you want to use the dehumidifier. Then look for a dehumidifier that is rated for a slightly bigger space. For instance, If the biggest room in your house is 500 square feet, a dehumidifier rated for 500 to 750 square feet would be okay. But it should not be smaller than that. Such a dehumidifier has a drainhose, so you won’t need to empty the bucket. 

3. The evaporator thermistor is broken

The dehumidifier thermistor is a small part that plays an important role in communicating the need for the defrosting process to begin. It is a temperature sensor on the dehumidifier evaporator coils.

Remember, a dehumidifier should blow warm air. However, this only happens when the temperature is okay since compression dehumidifiers work within certain temperature ranges (above 20 degrees Celsius).

If the evaporator coils get too cold, the thermistor sends a signal to the control board. It starts the defrosting process so that the unit can start drawing moisture from the air again.

If the thermistor is broken, the defrosting process will not take place. Thus, the dehumidifier will keep running all the time because it will not be drawing moisture from the air.

Solution: Buy a new evaporator thermistor on eBay, Amazon, or the website of your dehumidifier manufacturer. It is small, affordable, and easy to replace.

4. It is low on refrigerant

The old dehumidifiers use Freon. This refrigerant is not intended to be refilled, as it is added to last the lifetime of the unit.

However, an accident could happen, and the Freon leaks. If that happens, the unit will not work as it should. It will either shut down all the time or run continuously.

There is a simple way to know whether the dehumidifier has enough refrigerant. If you check the coils while the unit is running, you should see signs of frost forming over the coils.

That is an indication that everything is working as it should. If you do not see the signs of frost, it means the unit is not drawing moisture from the air.

5. Broken compressor

The compressor is a very important part of your dehumidifier. The dehumidifier draws the air from the room and passes it over the evaporator coils, where the moisture in the air condenses and drips into the collecting pan.

The compressor is the enabler of this process, and if it fails, the unit will not draw moisture from your indoor air.

The compressor can fail due to many reasons. For instance, it can fail when something blocks airflow to it. It can also fail when there is a high buildup of grease on the coils.

Solution: If you clean the coils and improve the airflow by making the dehumidifier grille side face open, you should just buy another dehumidifier. Replacing a compressor can be almost the same as buying another dehumidifier.

Is it normal for a dehumidifier to run all the time?

If there is high humidity inside the room, such as in the basement after flooding, it is normal for a dehumidifier to run all the time.

However, when you check the hygrometer and realize that the humidity is low, but the unit continues running, something is broken.

When running without lowering moisture, the dehumidifier blows cold air. You can place your hand against the grille or vents to feel whether the air coming out is warm or cold.

If it is cold, it means the unit is not lowering the humidity. Therefore, the humidistat will keep recording the humidity as high, and this will keep the dehumidifier running all the time.

When a unit runs without lowering humidity, it can cause the growth of mold in the house. Of course, exposure to this fungus will cause mold toxicity symptoms.

Do dehumidifiers use a lot of electricity?

If your dehumidifier runs constantly, you will be concerned about the cost it will add to your electricity bill. Generally, dehumidifiers consume electricity moderately. The compression dehumidifiers consume less than the desiccant units.

However, that won’t matter very much if the unit runs consistently 24/7. The dehumidifier is actually designed to run for several hours and stop for some time.

If the indoor humidity level is 90% in summer, the dehumidifier just has to lower it to 50%, and then it will switch off automatically.

Any electric appliance that is not maintained properly will consume more energy. Therefore, take good care of your unit.

Clean it often, paying special attention to the evaporator coils, since they get more dirt buildup. Also, check that the vents are not blocked.

Wrapping it up

A dehumidifier can run constantly, for sure, especially the big basement dehumidifiers for mold. However, it shouldn’t run 24/7, a full week or month.

Always keep an eye on the hygrometer. If you enter the right humidity settings in the control panel of the dehumidifier, it should stop when the set humidity level is reached.

Know how to follow the dehumidifier instructions to set the humidity level properly. This is going to give you the best