When to Turn Off a Dehumidifier

dehumidifier inside lg

Dehumidifiers play a significant role in improving the quality of indoor air by eliminating unwanted moisture. As a result, it assists in reducing respiratory challenges and allergies and prevents the destruction of your house by preventing a mold build-up. But you might be wondering: how long can a dehumidifier operate per day, and when should you turn it off?

You can immediately switch off your dehumidifier after realizing its relative humidity is below 30-50%. Some humidifiers also have an automatic shut-off feature when the device reaches a specific humidity level or full reservoir.

Here, we explore everything related to the operation and turning off of a dehumidifier

What is a Dehumidifier & What is its Function?

Before we focus on when you can turn off your dehumidifier and how long it should operate, we should understand what the product is and what it does. A dehumidifier is a device used to eliminate excess moisture from the environment. 

It achieves its function by reducing the relative humidity of the surrounding air. The device pulls in the air via the inlet, condenses it, heats it, and releases dry air. As the moisture in the surrounding air sucks out, the humidity of your room will drop gradually. 

Most dehumidifiers switch off automatically upon reaching the required humidity level. There is, therefore, no need to turn off the dehumidifier manually. 

Even though dehumidifiers are convenient and easy to use, there are still some questions that most people ask. However, the device presents the following benefits:

  • Reduces humidity levels: Dehumidifiers are known for reducing humidity levels, thus making your home less conducive to mold, mildew, and dust mites. 
  • Many dehumidifiers are quiet: The devices aren’t disruptive to your daily life, and most operate efficiently and quietly in the background even without realizing it. 
  • Helps with mold: The products assist in reducing odors associated with mildew and mold in your home. It might remove that rotting or musty smell completely. It also eliminates the possibility that you’ll develop mold on your furniture, clothing, and other linens. 
  • Betters your health: They also help prevent irritation on your respiratory system and skin, thus allowing you to feel comfortable and breathe easily. 
  • Less rust & fresher clothing: If you have a less humid environment, your clothes and cereals will dry faster and remain fresh for longer. It’ll also be difficult to notice signs of corrosion or rust on important things such as work tools, electronics, and computer equipment. 
  • Reduces dust: Operating a dehumidifier assists you in reducing dust in your house. You’ll therefore do less cleaning. 
  • Saves money: The device will enable you to pay fewer electricity bills by allowing your air conditioner to operate efficiently. A humid air means an air conditioner must overwork to remove the moisture and cool the air. The A/C will also wear out quickly. With a dehumidifier, the opposite happens. 

What is RH (Relative Humidity)? 

Relative humidity represents the percentage of moisture or water vapor in the air at a specific temperature. The ideal relative humidity is 30-50%.

At this relative humidity, you can breathe effortlessly with fewer microorganisms such as mildew and mold in the atmosphere. 

The relative humidity is different from humidity. Humidity represents the actual amount of vaporized water in the atmosphere. 

How Long Should a Dehumidifier Operate Per Day?

It’s advisable to operate a dehumidifier for about 12 hours a day. However, the duration depends on the room size, appliance’s built-in features, unit capacity, running cost, and room dampness condition. 

The dehumidifier might need to operate for the whole day if your room is exceptionally wet. If such is the case, your device must have an auto shut-off feature.

The auto shut-off function turns off the dehumidifier when it reaches a specific humidity level or full reservoir. 

Some dehumidifiers come with a different alternative in a continuous pump linked to the floor drain. The pump will drain water when it accumulates in the tank. You’ll therefore have fewer worries when it comes to emptying the tank. 

However, if your dehumidifier lacks such features, you’ll have to check the device manually time and again. It is to ensure that there is no water overflow to damage your floor. 

It would help to understand that there are no established rules on the length of time that a dehumidifier can operate. However, in the case of humid air, you must specify the cause of the excess humidity instead of keeping the dehumidifier on constantly. 

Should a Dehumidifier Operate Constantly?

You don’t need to leave your dehumidifier in constant operation. It’s just enough to operate the device when humidity is above 50%. However, we recommend always maintaining a humidity level of 30-50% for your home. 

It’s also essential that you don’t set the humidity too low. You’ll end up wasting money and energy since your device will operate when it’s not supposed to.

Additionally, constantly operating the dehumidifier means its tank will always fill. The device should therefore have a pump to drain water automatically or an auto shut-off feature. 

Is it Safe to Let Your Dehumidifier Operate the Whole Night?

There is nothing wrong with allowing your dehumidifier to operate all night as long as it doesn’t affect your health. However, there are things to note before allowing your device to work throughout the night. 


A dehumidifier has a compressor that produces a wind noise when taking in and emitting air. It can disturb your night’s sleep. If you plan to use your device through the night, it will help check its sound output. 

On & Off Feature

Since you won’t be touching your dehumidifier while sleeping, it would help to have an auto-on/off switch. The switch will automatically shut off your dehumidifier after removing the required moisture amount from the air. 

The compressor constantly switches on automatically if the humidity level exceeds the selected setting. 

Tank Capacity

Your dehumidifier should come with a tank having sufficient capacity. It allows for continuous use to prevent your room from getting filled with water. With an adequate tank, your dehumidifier can have a constant drain pipe or an auto shut on/off feature. 

When to Turn Off the Dehumidifier

We recommend that you turn off your device for a few months as summer approaches its end and you begin with heating your house for winter. Turning off the unit will save you money since there is no point in having it on unnecessarily. 

After all, the winter air is drier compared to the summer air. 

The Cost of Operating a Dehumidifier 24/7

You don’t have to operate your dehumidifier 24/7. Most latest models are designed with a humidistat to control everything. A humidistat automatically switches off the dehumidifier when it’s not getting rid of the humidity in the air. 

There is a much better approach to determining the cost of operating a dehumidifier throughout the day. You must multiply the dehumidifier’s working hours by the device’s hourly energy consumption. 

Suppose you were running it 24/7 all year long. That would cost you roughly $0.72 to $3.84 per day. However, it is doubtful that you’ll pay upwards of that much daily.

It will likely cost less than a dollar each day to run. In another case, running the dehumidifier for about 8 hours a day will be about $15 a month.

It’s also important to remember that dehumidifiers have a lifespan and could potentially last several years with proper use. Using your dehumidifier 24/7 will increase the running costs and stress the compressor. 

The tips below prevent the staining of your dehumidifier and, if followed, can help to reduce its operating costs. 

1. Always Keep Your Device in a Properly Ventilated Spot

Having proper ventilation around your device helps since it allows air to flow in and out freely, thus enabling the unit to work efficiently.

It would be best if you also remembered that door and window cracks allow more external mixture into your room. Sealing such cracks will prevent excess moisture in your home and strain the dehumidifier. 

2. Avoid Using Heating Appliances When Your Dehumidifier is in Use

Kerosine and natural gas heaters are known for contributing to increased room moisture. Using them will therefore mean that the dehumidifier will operate for longer hours, thus straining it. If you must use a heater, we recommend going for electrical heating appliances. 

3. Keep Your Reservoir Empty

Your dehumidifier won’t operate at optimal capacity if the tank is full of water. You also risk the water causing damage to your circuit boards. In the end, you’ll have an added maintenance cost you weren’t ready for. 

Therefore, it would help keep the tank empty by either using the auto shut-off feature or a drain pipe. 

4. The Kitchen & Bathroom Require Exhaust Fans

Installing fans in the kitchen and bathroom will help to reduce the dehumidifier’s operating costs. Thanks to the hot baths and showers, there is more moisture in your bathroom.

The kitchen is another humid place, thanks to the cooking that happens there—exhaust fans such moisture from the environment, limiting the stress on your dehumidifier.

5. Keep the Air Vents & Coils Dust-Free

The dehumidifier’s air vents and coils accumulate dust that may damage and clog the unit’s internal components. You can prevent such a situation by gently using a brush to remove the dust. 

Besides, having less dust in your unit ensures that it runs cost-effectively. 

Turning Off a Dehumidifier

Let’s assume that your dehumidifier has been operating efficiently in tandem with the central air conditioner through the summer to keep your home comfortable, cool, and at the perfect relative humidity level.

When summer approaches its end, the focus shifts to home heating, and it is time to turn off the dehumidifier, but how do you go about it? 

In most cases, you can forget because most dehumidifiers operate automatically, with no action needed from you to turn it off. However, having the device off during winter can help you save money.

Your house will be more comfortable during winter when its relative humidity is higher. Since winter air is drier than summer air, you don’t need a dehumidifier during winter. 

You can strictly follow the steps below to turn off your dehumidifier when winter kicks in:

  1. Set your dehumidifier’s built-in humidistat to the highest relative humidity or off position to prevent operation. If it’s difficult to locate the humidistat, you can check the return air plenum near or above the unit. It may also be installed on the wall closer to your thermostat. 
  2. Switch the bypass duct damper to the ‘winter’ position or close it. However, you should understand that not all units come with a damper. If your unit has a damper, it’ll be found in the round duct linked to the unit. 
  3. Clean and dry the dehumidifier surfaces to prevent mildew and mold from growing. It’ll offer a more seamless setup when spring kicks in, and you must put the device back to service. 

If turning off your dehumidifier sounds complicated, you can ask a professional technician to help you out. 

Why the Dehumidifier Won’t Shut Off Even When the Humidity Level is Met

If your dehumidifier filters become dirty and the fans keep operating, the device won’t shut off even when it meets the humidity level.

Ensure you turn off the continuous mode to help the compressor turn off once the target humidity meets. The dehumidifier stops when the compressor stops. 

There are times when the frost in the coils prevents the fan from stopping. The fan will keep operating even when the compressor is off until the device defrosts. 

If you have fixed all the challenges above and your unit does not automatically shut off, you’ll need to check the user’s manual. You can also contact customer care using your email, name, and purchase details.

Are Dehumidifiers Better in Winter or Summer?

Regardless of winter or summer conditions, dehumidifiers should be employed every time the relative humidity is high. Excess moisture during winter or summer can damage your home’s structural integrity and affect your health. 

During summer, your room’s temperature is a bit high. Because it’s higher, you can use an air conditioner and dehumidifier to dehumidify and cool your home. 

High humidity and lower room temperature significantly affect indoor air quality during winter, especially in the attic, crawl space, and basement space. 

It’s common knowledge that the cold winter air has less moisture. However, most of the time, we always seem to ignore the indoor factors that increase your home’s humidity levels, even during winter. 

For instance, steaming, nurturing plants, cooking, and using a clothes dryer increase the relative humidity in your home by about 50%, even when the outdoor temperature is below zero degrees Fahrenheit.

The vents in your attics and basements cause ice and water to seep inside, thus lowering the indoor temperature and increasing the basement and attic humidity. 

To ensure structural integrity and good health, we recommend that you also operate a dehumidifier during winter. However, avoid utilizing the device for longer hours. You can use a hygrometer to measure every room’s humidity and indoor temperature. 

You need to switch on/off your device in winter based on your humidity level. 

Cold temperatures during winter lead to the freezing of compressor coils in your dehumidifier. The challenge might force the unit to stop and malfunction in one way or another. You should therefore find practical setpoint functionalities to operate your dehumidifier during winter. 

The best approach is to employ a dehumidifier with an auto defrost facility and hot gas valve defrosting system. The functionality defrosts your dehumidifier automatically and prevents its breakdown during winter. 

Setting Your Dehumidifier

After purchasing a dehumidifier, the hardest part is setting it up for use. However, setting your dehumidifier can be easy if you understand the steps.

Step 1: Select the Best Dehumidifier Location

Installing your device at the best location will impact its efficiency. Portable units work best in any room that they’re required. 

You can review your user manual for any furniture or wall clearances. Place the unit closer to your room’s center. 

Step 2: Set Up the Moisture Draining

Here, there are three options to consider:


It doesn’t require any additional setup. However, it would help if you emptied the unit’s tank when it gets full. 

Gravity Draining

Link a hose at the back of your device and collect moisture to the floor drain directly. 

Condense Pump

The option offers the most convenient moisture removal approach. A pump effectively pushes the moisture out of the unit to a different location. 

Step 3: Set The Perfect Ideal Level

A dehumidifier has an onboard humidistat that maintains the humidity level automatically. We recommend that you keep the humidity level between 45 to 50%. It’s the perfect humidity level range to prevent mildew and mold from thriving. 

Below are steps on how to set the humidity level:

  • Start by plugging in your dehumidifier.
  • Turn the dehumidifier on.
  • Adjust humidity levels on the control panel from 45 to 50%. 
  • The device will operate to maintain the set humidity level. 

Step 4: Check the Progress

After installing the dehumidifier and operating it, it would help ensure it functions properly. For instance, you should ensure that the condensate pump drains your moisture effectively. 

Clean the filters regularly and check the manual for additional maintenance tips. 


A dehumidifier improves indoor air quality by eliminating unwanted moisture. Therefore, it helps prevent the destruction of your property and plays a part in reducing allergies and respiratory challenges.

When you notice the relative humidity below 30-35%, you can immediately switch off your dehumidifier. However, the device has an auto switch on/off feature that automatically turns off or on, depending on humidity. 

For the durability and effectiveness of your dehumidifier, you must implement regular maintenance.


Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.