How Long Does It Take For A Dehumidifier To Work? [7 Crucial Factors]

We don’t want to see mold and mildew, but they do appear on occasion in the house. We’ve heard how effective a dehumidifier is at removing excess moisture, but we’re not sure how long it will take to work.

Please be patient! On average, a dehumidifier will take 8 to 12 hours to work. However, the amount of time spent is determined by a variety of factors, including your device’s capacity, humidity level, room temperature, room size, and so on. As a result, there is no one-size-fits-all answer to this question.

I’ll go over these factors with you to help you estimate the time more accurately. In addition, I’ll explain how to tell if your dehumidifier is working.

On average, how long do dehumidifiers take to work?

Dehumidifiers do not require any warm-up time. When you plug it in and select the model, it will immediately begin to work.

However, unlike an air conditioner, it may not be able to make a significant difference in a short period of time.

When you first get your device, it is often recommended that you run it continuously for one or two weeks to ensure that the humidity level in the room is kept within an ideal range.

But in this post, our focus is on how long it will take for a dehumidifier to reduce the humidity to a comfortable range like 40% to 50% or make a noticeable effect. After asking a few of my friends and testing the two models I have, 8 to 10 hours should be the average time a dehumidifier needs to take. 

Nonetheless, this is just a rough estimate. There are many factors that will affect it so the result you get may be totally different from mine. 

Factors that affect the time a dehumidifier takes to work

Now that you know that time spent will vary, let’s look at 7 critical factors to consider when estimating it.

1. Types of dehumidifiers

Dehumidifiers are classified into two types: refrigerant dehumidifiers and desiccant dehumidifiers. However, most American families prefer compressor models because they are more energy-efficient.

However, due to their operating principles, compressor dehumidifiers cannot function properly below 65°F. As a result, it is not uncommon for a compressor model to operate more slowly than a desiccant model.

Furthermore, a whole-house dehumidifier is more powerful than a portable dehumidifier. It may take less time to work. 

Because they are designed to address large spaces, commercial dehumidifiers typically take less time to work than residential dehumidifiers.

2. Capacity 

The dehumidifier capacity often refers to how many pints of water a dehumidifier can remove every 24 hours. The larger the capacity, the more appropriate the device is for a larger room. 

That is to say, the model with a larger capacity will take less time to work if the room size is unchanged. 

I personally have a mini dehumidifier, and I noticed that it seems never to be able to reach my target humidity level in a day if I put it in my living room. However, my Hisense one will only take 3 to 4 hours to work in my small study.

3. The starting humidity level

The humidity level is critical. If your room is not overly damp, such as with a relative humidity of 55 percent, a medium-sized dehumidifier should be able to reduce the humidity to 50 percent in 1 or 2 hours.

If your basement has a flood or other water damage, drying will take much longer, usually a few days.

4. Your target humidity level

The ideal humidity level is between 35% to 55% in general. That is, you will feel comfortable when you set it at either 40% or 50%. 

However, for a dehumidifier, 40% or 50% will make a significant difference. If the starting humidity level is 65%, it will take a few hours longer for a dehumidifier to reduce it from 65% to 40% than from 65% to 50%.

You don’t have to pursue an extremely low level. As long as it is within a certain range, it should be fine. In this way, you can save more on energy costs.

5. Room temperature

how fast do dehumidifier work

Suppose the indoor humidity level is the same, the higher the temperature, the more water vapor the air can hold. 

So on warmer days,  it could be more challenging for a dehumidifier to reach a proper humidity level because it has to remove more water from the air. 

That’s why we recommend people set the humidity level in the basement at 50% in summer and 40% in winter.

6. Room size

If you move your dehumidifier to a different room, the time it takes to dry will change accordingly.

The larger the room, the more excess moisture there is to be removed. You should expect it to take longer to work if you do not use another dehumidifier.

7. Type of your room 

Some rooms are close to water sources and prone to water leaks, such as the bathroom, kitchen, and basement.

If you plan to dehumidify these rooms, the humidifier will take longer to work because these places are usually the dampest areas in the house. 

How to make your dehumidifier work faster?

It is critical to select a dehumidifier that is appropriate for the size of the room. It ensures that excess moisture is effectively removed without causing dryness.

When running your dehumidifier, keep the windows and doors close and put it close to the moisture source

On top of it, you can use a dehumidifier with a fan together since the fan can help the moisture in the corner get into the machine more accessible, reducing humidity in the whole room quicker.

How to tell if your dehumidifier works?

A hygrometer is the best way to tell if your dehumidifier is working. In fact, many dehumidifiers include a built-in humidistat that allows them to turn on and off automatically.

High humidity can cause condensation on windows, allergic reactions, and breathing difficulties. If you notice that these symptoms have subsided or have disappeared, this indicates that your dehumidifier is functioning properly.

Check here to know more ways to tell if your dehumidifier is working.


A dehumidifier effectively decreases moisture levels but takes some time to work. 

How long does it take for a dehumidifier to work? There is no single clear-cut answer to this question. Various factors, including the room size, ambient temperature, and the starting and target humidity level, will play a role in the time spent. But allowing it to run 8 to 12 hours is generally adequate to ensure it can make some telling impacts. 

You see, a dehumidifier will not take too long to work. Let’s get started!

You may also want to know how long it takes for a humidifier to work.

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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 a lot 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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