How Long Should A Dehumidifier Run Per Day?

As more people become aware of the importance of controlling humidity at home, they decide to try out a dehumidifier. When my friends got their first dehumidifier, they all had the same question: how long should a dehumidifier run?

In general, you should run a dehumidifier for 8 to 12 hours per day. However, it is affected by the room temperature, indoor humidity level, target humidity level, and dehumidifier capacity.

So, how do these factors affect your machine’s runtime? And can you leave a dehumidifier running all night? This post will teach you how to properly control the runtime of your dehumidifier in order to get the most out of it.

Factors affect how long a dehumidifier should run 

While the average runtime is about 8 to 12 hours, it doesn’t mean that running it in such a period of time is adequate for you. There are many considerations.

The starting humidity level 

The ideal indoor humidity level is around 30% to 50%. Whenever the humidity level is above 55%, you can turn on a dehumidifier.

Depending on what the humidity level is, the time taken for a dehumidifier to work varies. The basement, for example, is typically wetter than other areas of the house. You should run the machine for a longer period of time than you would in the bedroom.

Furthermore, because summer is more humid than winter, the runtime will be extended accordingly. In fact, the vast majority of people do not use a dehumidifier at all during the winter months.

The target humidity level

The preferred moisture level is different for everyone. Even if the dehumidifier has reduced the humidity to an ideal humidity level, you may still want to extend the runtime.

For instance, 50% is a comfortable humidity level for me, whereas 40% can make my mom feel better.

My dehumidifier has to run for about 12 hours to maintain a 40% level, but it can reach 50% in about 6 hours. So the time it takes for me to leave a dehumidifier on is much shorter than for my mom.

Capacity of your dehumidifier 

The dehumidifier capacity decides how much water it can collect per day. When dealing with the same space, a commercial dehumidifier should run for less time than residential models since it is more powerful.

If you want to cut down the runtime, you should pick a larger dehumidifier. Otherwise, the machine may run for a few days until it reaches the target level.

Room temperature

At the same relative humidity level, the warmer air will hold more moisture than the colder air. Therefore, the machine will run longer when the room temperature is high, assuming the target and starting level are unchanged.

Beyond that, the compressor dehumidifier can’t work properly below 65°F, which will prolong the runtime of your machine as well.

How to shorten the runtime of a dehumidifier?

If the machine can run for less time per day, it can save you a bunch of money in the long run.

To shorten the runtime, it is important to keep the doors and windows closed when the machine is turned on. Cleaning the air filter is also helpful in maintaining the machine in a good state.

Some models will shut off automatically when the water tank is full. If you want the machine to keep running, you should empty it regularly or drain the water through a drainage hose if there is a drain port on the back.

Placement is also important. Putting it close to the source of humidity can improve the efficiency of your appliance.

But addressing the root cause of the humidity problem is the ultimate thing to do. You can shorten the runtime a lot or even stop using a dehumidifier when the issue is solved. The damaged roof, leaky pipes, and poor-ventilated bathroom are often the culprits.

Should a dehumidifier run constantly?

should you run a dehumidifier constantly

No. There is no need to run a dehumidifier constantly. As long as the humidity level is lower than 50% or maintained at any level that you feel comfortable with, you can turn off the machine after 8 to 12 hours every day.

If you run a dehumidifier 24/7, it will use a lot of electricity, which is not necessary in most cases.

Furthermore, if the model doesn’t have a built-in humidistat, it will cause dryness, which is as bad as dampness for our health.

However, if your basement just had a flood or it is your first time running a dehumidifier in the room, you can run the machine constantly for a few days or extend the runtime per day.

Is it safe to run a dehumidifier constantly all the time?

Yes, it is generally safe to run a dehumidifier all the time. As I said, modern dehumidifiers come with a humidistat, so they will shut off and on automatically when a certain level of humidity is reached.

As a result, the machine will not run at its maximum power all the time and be able to run constantly.

If you intend to run a dehumidifier for a longer time per day, you’d better opt for an energy star rated model which can save about 15% less electricity.

Running a dehumidifier all night is a good idea. It makes sure your sleep quality will not be interrupted by allergic reactions and breathing difficulties.

Nevertheless, many dehumidifiers are noisy. You can set them to “sleep mode” or only run them in the daytime.


Generally speaking, you should run a dehumidifier for 8 to 12 hours per day to maintain your room at a comfortable level.

If the environment is too humid or you prefer a lower humidity level, you should run it even longer. Running a dehumidifier all night or all day is fine as long as you don’t mind the noise or the high electricity bill.

About The Author

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested dozens of products in person, like humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

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