Is It Safe to Run a Dehumidifier Constantly?

Lisa Borga
by Lisa Borga

If you have a damp house or maybe just a damp room, you may be considering purchasing a dehumidifier. Or, quite possibly, you already have one and wonder if it’s safe to run a dehumidifier constantly. Dehumidifiers are great for reducing moisture in your house, but if moisture is a major issue, a dehumidifier might not be a permanent solution.

It is safe to run a dehumidifier constantly without harming the device, but it is unnecessary and can increase your energy bills. You should run your humidifier when the relative humidity is above 50% to maintain a comfortable level of 30% to 50%. Make sure to not set the humidistat too low, or the unit will run when it doesn’t need to.

More About Dehumidifiers

A dehumidifier works by using a fan to draw in air, which then runs through cooling coils. Then, these coils remove moisture from the air through condensation. You will typically need to empty the condensed water from a collection bucket unless your dehumidifier empties into a drain.

Dehumidifiers come in two main types: desiccant and refrigerant. These dehumidifiers use different technologies to remove moisture from the air.

Desiccant dehumidifiers remove moisture by moving the air through a rotor containing a desiccant that absorbs moisture. During part of this cycle, the rotor is exposed to heat, which causes the moisture to evaporate. As a result, it allows the desiccant to continue to work.

Refrigerant dehumidifiers remove moisture from the air through condensation. In brief, the machine draws air from the home and moves it over cold evaporator coils, which cools the air.

Then, the moisture condenses and is collected. Next, the air passes over warming coils lowering the air’s relative humidity. This returns the air to the home’s temperature before leaving the machine.

Benefits Of A Dehumidifier

A dehumidifier provides many benefits to homeowners. Dehumidifiers do this by lowering the relative humidity in the space in which they are placed. This prevents mold and bacteria from propagating in humid conditions.

For this reason, if you have ever had problems with mold in your bathroom, you will appreciate a dehumidifier preventing this from happening. Additionally, they typically include an air filter generally improving the air quality in your home.

In addition to health benefits, a dehumidifier will protect the structural integrity of a home. Chiefly, by decreasing the humidity, you reduce the chance that condensation will form and warp the structure of your walls. You may also keep your home looking better since too much moisture may cause your paint to peel.

Also, a dehumidifier can actually improve the health of people in homes that have one. Notably, people with allergies or asthma will find a dehumidifier particularly helpful. Additionally, since moisture attracts pests such as roaches and spiders, a dehumidifier could improve your health by reducing these pests.

Do You Need to Run a Dehumidifier Constantly?

In short, it is not necessary to have a dehumidifier running constantly. It should only be run when the humidity level in your home is above 50 percent. The optimal comfort levels for a home are generally between 30 and 50 percent humidity.

The key with dehumidifiers is to avoid setting the humidistat too low. This will waste energy and keep the unit running, even when it should be turned off. If you decide to keep your humidifier running all the time, you must choose a unit that has the ability to drain water automatically.

However, constant use of a dehumidifier is not recommended for a number of reasons.

Disadvantages of Running A Dehumidifier Constantly

It is not dangerous to run a dehumidifier 24/7. Still, it could shorten the lifespan of your machine and raise your energy bills. Also, dehumidifiers make noise when they run, so the constant sound might become annoying.

Furthermore, overuse of a dehumidifier may lead to health problems such as dry skin or dry eyes. Even worse, it could cause a dry respiratory tract, thus increasing the chance of developing an infection.

Determining The Size Of Dehumidifier You Need

For a Dehumidifier, size is determined by the amount of water the machine can remove every twenty-four hours. The water a device can remove is measured in pints per day, shortened to PPD.

Typical machines remove 30, 50, or 70 pints per day. However, you can purchase mini dehumidifiers that will remove less than 20 pints per day. Also, some stores carry household dehumidifiers that will remove nearly 200 pints per day.

You can estimate the machine you will need by checking the square footage of your room and the dampness level. Then, check the chart below to help you decide what size machine you will need:

Dampness LevelSquare Feet


Square Feet


Square Feet


Square Feet


Moderately Damp10 pints20 to 40 pints50 pints30 to 40 pints
Damp20 t0 30 pints30 to 50 pints50 to 60 pints40 to 50 pints
Wet40 to 50 pints50 to 60 pints70 pints45 to 60 pints
Very Wet50 pints60 pints70 to 100 pints50 to 70 pints

What Causes A Dehumidifier To Run Constantly?

If your machine runs 24/7 after being set to 50% or lower relative humidity level, something is wrong. Several factors can cause a dehumidifier to run constantly. First, make sure your dehumidifier is set to turn off at 30% to 50% relative humidity.

Leaving a dehumidifier running nonstop will not harm anything. However, it will shorten your machine’s life and won’t do much good if the humidity in your home remains high. If it must run continuously to reach comfortable humidity, consider solving the source of the problem. There are several likely root causes of consistently high humidity.

Problems That Can Run A Dehumidifier Constantly

  • Your machine is in too cold an environment and has frozen coils. So, it is no longer removing humidity from the air.
  • Your machine does not have an auto-shutoff. If this is the case, you may wish to turn the machine off when you are away. This will allow the machine’s compressor to rest and avoid wasting energy.
  • Something is wrong with your AC system. If you are running a central AC, it should be lowering your home’s humidity. However, if it is not, check if it is releasing liquid from its exhaust hose — if not, it may be clogged.
  • Rising damp could be causing excess continuous humidity. This is when pores in some kinds of walls draw moisture up from the ground through capillary action.
  • If your ground level is too moist, a crawlspace could be a source of moisture rising. If it is left too long, you might also notice mold developing on the walls near the ground level. You may have to remove the mold before fixing it, which will probably require professional attention.
  • You don’t have enough exhaust fans. A lack of exhaust fans in bathrooms and the kitchen can leave moisture from showers, cooking, and washing dishes.

Alternatives To Running A Dehumidifier Constantly

If you need to run a dehumidifier too often or if it is just too costly, consider alternatives. Instead of overrunning your dehumidifier try these:

  • Use desiccants. Place desiccants like calcium chloride around your house as these absorb moisture and trap it. Then, you just need to empty the water and refill it with more desiccant.
  • Place fans. By placing fans in moisture-laden areas, you can redirect it to dryer areas of your home. Generally, the most effective method is to use window fans and exhaust the air out of your home.
  • Open windows. Simply opening a window in your bathroom or kitchen when you shower or wash dishes can let the moist air out.
  • Run an air conditioner. Air conditioners work as a dehumidifier without reheating the air before blowing it out. If you are using a central ac unit, consider running it some more otherwise a window ac unit can do.

Related Questions

Should I leave my dehumidifier running when I go on vacation?

This depends on what type of dehumidifier you own. Chiefly, you would need to have a humidifier that can be set to automatically maintain a certain humidity level. Also, the machine would need to be set to discharge into a drain.However, if you have a humidifier that does this, your house will probably be in better condition when you get home.

Do dehumidifiers kill mold?

Removing all of the mold spores from a mold-infected home is nearly impossible. When there’s no excess moisture for mold to grow, it will stay “dormant” in the air. Then, once humidity increases, mold can start to form on clothes, walls, and more.Therefore, dehumidifiers do not kill mold, but they can prevent it by reducing humidity in your home. To remove mold, you need to stop the source of the moisture.

Is water from a dehumidifier drinkable?

Whether the water that your dehumidifier collects is drinkable will depend on how long the water has been sitting around and how clean you keep your tank. However, the water from a dehumidifier tends to be very clean; equivalent to distilled water.So, assuming that your coils are kept clean and the water hasn’t sat in the tank for too long, you could actually collect the dripping water and drink it.

Lisa Borga
Lisa Borga

I am a writer who enjoys working on home improvement projects. My husband was in the navy, so we moved frequently. This gave me many opportunities to fix up new places. In my spare time, I enjoy reading mysteries and hiking.

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