How Long Should a Dehumidifier Run Per Day

Dehumidifiers play an essential part in improving indoor air quality by removing unwanted moisture. In the process, it helps alleviate allergies and respiratory problems and can also avoid damage to your home by preventing mold build-up. 

Dehumidifiers also help maintain the temperature and relative humidity at an ideal level by constantly collecting water from the air. But you may wonder: how long should a dehumidifier run per day?

What is a Dehumidifier, and What Does it Do

A dehumidifier is a household appliance used to remove excess moisture from the environment. It reduces surrounding relative humidity. It pulls in air through its inlet, condenses, heats, and releases dry air out. The room’s humidity gradually drops as the moisture in the air is sucked out. 

Most dehumidifiers automatically switch off upon reaching the desired humidity level. While dehumidifiers are easy and convenient to use, these are common questions people ask.  

How long should a dehumidifier run per day

What is Relative Humidity (RH)?

Relative Humidity is the percentage of water vapor in the air at a given temperature. The ideal RH is between 30-50%, where you breathe comfortably with fewer microorganisms like mold and mildew in the atmosphere. RH is not the same as humidity. Humidity is the amount of vaporized water in the air. 

How Long Should a Dehumidifier Run Per Day?

It is generally better to run the dehumidifier for at least 12 hours a day. However, it depends on the appliance’s built-in features, room size, room dampness condition, unit capacity, and running cost.

It may need to run for the whole day if the room is exceptionally wet. If this is the case, the unit should have an auto shut-off feature. It turns off the device once the reservoir is full or reaches a specific humidity level. 

Some dehumidifiers have another alternative in a continuous pump connected to the floor drain. It drains the water as it accumulates in the tank. This way, there’s no need to worry about emptying the water tank. 

But if your appliance doesn’t have any of these features, you will have to check the unit manually now and then. It’s to ensure the water doesn’t overflow and damage your floor. 

There are no established rules on how long the humidifier can run. 

However, if the air is humid, it’s better to determine the root cause of this excess humidity instead of just keeping the dehumidifier switched on constantly.

Read our Dehumidifier vs Air Purifier Comparison

Should a Dehumidifier Run Constantly?

No, there is no need to keep the dehumidifier running constantly. It’s generally enough to run the unit when the humidity level is 50% or higher. A good rule of thumb to remember is to maintain a comfortable 30-50% humidity level for most homes. 

However, don’t set your humidistat too low. You end up wasting energy and money because the unit runs when it doesn’t need to and should actually turn off. 

Besides, if you run a dehumidifier continuously, remember that its tank will keep filling. So the unit should either have an auto shut-off feature or a pump to drain the water automatically. 

Related article: What Happens If a Humidifier Runs Without Water for a Long Time?

Is it Safe to Leave a Dehumidifier on All Night?

Yes, there’s nothing wrong with leaving the dehumidifier on all night if it’s okay health-wise. There, however, are a few points worth knowing before opting to leave it on all night.

  • Noise

The dehumidifier’s compressor makes a wind noise while taking in and exhausting air, which can disturb your sleep. It’s better to check the unit’s sound output if you plan to use it all night. 

  • On/off feature

As you won’t be touching the dehumidifier while you are asleep, it’s better if it has an auto shut on/off switch. The switch automatically shuts the unit off after removing the desired moisture from the air. The compressor will anyway automatically switch on once the humidity level exceeds the selected setting. 

  • Tank capacity

As mentioned earlier, the dehumidifier should have a tank with sufficient capacity for continuous use to prevent a room full of water. Alternately having an auto shut on/off switch or a continuous drain pipe also helps. 

When Should I Turn Off My Dehumidifier?

It’s better to shut off the dehumidifier for a few months as summer comes to an end and you start with heating your home for winter. Turning off the dehumidifier saves you money because there’s no point in keeping it on unnecessarily. After all, cold winter air is drier than summer air. 

How Much Does It Cost to Run a Dehumidifier 24 Hours a Day?

You don’t generally have to run a dehumidifier 24 hours a day. Most of the latest models have a humidistat. It sets the humidity levels and automatically switches off when they no longer need to dehumidify the air. 

There is a clear-cut way to determine how much it costs to run a dehumidifier throughout the day. Multiplying your unit’s hourly energy consumption with the number of hours it runs gives you the answer. 

The costs depend on the model and quality of your dehumidifier. Dehumidifiers, on average, cost anywhere between $25 to $350 to run a year. The portable mini dehumidifiers and homes that don’t use them much are the cheapest. The larger units that extract about 70 pints or more moisture from the air every day, can cost $350 a year to run. 

Dehumidifiers have a lifespan and can last a couple of years with proper usage. However, using a dehumidifier continuously for 24 hours a day stresses the compressor and increases its running costs. 

The following tips prevent unnecessary straining of the dehumidifier, which can, in turn, lead to increased running costs.   

1. Keep The Dehumidifier In a Well-Ventilated Spot

Improving ventilation around the dehumidifier helps because it lets air freely flow in and out and work efficiently. Conversely, window and door cracks lead to more external moisture entering the room. Sealing the room prevents extra moisture from entering the room and straining the device. 

2. Do Not Use Heating Appliances When Dehumidifiers Are In Use

Natural gas or kerosene heaters only contribute to the room’s moisture, keeping the unit running longer. Instead, replace them with alternate electrical heating appliances. 

3. Keep The Reservoir Empty

The dehumidifier doesn’t work at optimal capacity with a full water tank. There’s also the risk of the water damaging the circuit board, adding to its maintenance costs. 

4. The Bathroom And Kitchen Need Exhaust Fans

Installing exhaust fans in the bathroom and kitchen help reduce the dehumidifier’s running costs. It’s because there is more moisture generated in the bathroom, especially after hot showers or baths. 

The kitchen can also get humid with all the cooking going on there. Exhaust fans help suck out the moisture from the air, thus reducing the stress on the dehumidifier. 

5. Keep Coils And Air Vents Dust-Free

The dehumidifier’s coils and air vents accumulate dust that may clog and damage the unit’s internal components. It is best prevented by gently removing the dust with a brush. Besides, less dust in the dehumidifier operates it more cost-efficiently. 


In this article, we’ve discussed the question of how long should a dehumidifier run per day. The short answer is, it doesn’t matter. We’ve also discussed related questions.

Hopefully, we’ve answered most of your dehumidifier-related questions to help you make maximum use of your dehumidifier, both in terms of efficiency and benefits. 


  • I have a NORDIK, Model 87795066, MDCDP-30AEN1-BBON. Purchased in May 2020. It’s working great in removing the humidity out of my basement.

    My concern is that it will reduce the humidity to the level that I set, say 50%. When it reaches that level, the unit shuts off, but restarts within 5-10 seconds!

    I’m just not sure if a 5-10 second shut down is considered normal? Should it be longer?

    Not a huge problem, just being cautious!

    Looking forward to your response.

    Steinbach, Manitoba

    • Hi Bob, since you live in Manitoba and the general humidity level is 61%, it is possible your dehumidifier needs to be running constantly to keep the level at the set 50%. Is it perhaps different in less humid months such as May?

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