High humidity can cause a variety of problems in your home. To prevent any of these problems, dehumidifiers are highly beneficial and sometimes even necessary to reduce moisture and maintain healthy relative humidity levels. However, if you often suffer from high humidity in your area, you may be concerned about the safety of running your dehumidifier for long periods of time.
While it’s greatly effective in reducing humidity, there’s still a limit to its use. You can run it nonstop if you like, but this is often unnecessary and even harmful over time. Ideally, you should run your humidifier only when humidity is above the comfortable levels of 30% to 50%. Below we talk about the costs and possible effects of running your dehumidifier continuously and what you can do instead.
What Does a Dehumidifier Do?
The main purpose of a dehumidifier is to reduce humidity in an enclosed space. There are two main types of dehumidifiers based on the methods they use to remove excess moisture from the air: desiccant and refrigerant types.
Desiccant dehumidifiers reduce the humidity using a hygroscopic substance that absorbs moisture from the air. They are further classified by the capacity of the substance to hold water or dissolve into a liquid.
Electric desiccant dehumidifiers consist of a rotating wheel filled with desiccant, which draws the moisture from the air. The rotor is then heated and moisture transfers to the warm air, thus “renewing” the desiccant. This warm, moist air passes over the condenser, and water droplets form.
Refrigerant dehumidifiers remove moisture from the air through condensation. A fan draws in humid air and passes it over cold evaporator coils. As the air temperature decreases, moisture condenses and drips into the water tank. The dryer air passes over the warm coils before returning to the room.
Do You Need a Dehumidifier?
High relative humidity inside your home can cause discomfort and even lead to health problems and structural damage over time. You need a dehumidifier to reduce humidity and its harmful effects.
Maintaining optimal humidity prevents mold growth and dust mites, which are common triggers of allergic reactions such as sneezing, nasal congestion, runny nose, as well as eye and skin irritations. Exposure to mold spores can also trigger asthma attacks and other respiratory conditions. Dehumidifiers also come with air filters to catch dust.
Dehumidifiers improve your indoor air quality. Excess moisture in the air weighs it down and makes it difficult to breathe. Using a dehumidifier keeps out moisture and the resulting musty odors, ensuring your utmost comfort.
Dehumidifiers help your air conditioner to lower cooling bills. When the air is too warm and humid, you need more than just your AC to lower the temperature and humidity efficiently. Too much moisture in the air wears down your AC unit easily, so you need a device equipped specifically to remove moisture from the air.
Dehumidifiers also help preserve your furniture and the structure of your home. Maintaining the humidity level within the optimal range prevents condensation which can lead to peeling paint, rusting metal, and rotting wood. It can also reduce pests that thrive in high humidity environments.
Do You Need to Run a Dehumidifier Constantly?
The short answer is no, you don’t need to run a dehumidifier for 24 hours, seven days a week. In general, it’s only necessary to run the unit when the relative humidity reaches 50% or higher. Remember that the optimal indoor humidity level is between 30% to 50% to maintain your comfort. Anything outside this range can become harmful to you.
A standard residential dehumidifier today allows you to set the humidity level you prefer and it will maintain this setting automatically. You can usually set the humidity threshold between 30% to 80% on the dehumidifier’s panel, but note that the ambient temperature may also influence the ideal humidity in the space.
Many dehumidifiers also feature a Continuous function where the unit will run nonstop for a full 24-hour cycle. This can be a handy feature for heavily damp, large spaces like the basement, given that the unit is attached to a hose for automatic drainage. However, letting your dehumidifier operate continuously may also waste energy because the unit runs even when it doesn’t need to.
In most cases, the best thing to do is adjust the humidistat to the ideal humidity level. If the outdoor temperature is below 40°F, set the humidity to be not more than 40%. If the temperature is below 20°F, set the humidity to be not more than 35%. And if the temperature is below 10°F, set the humidity to be not more than 30%. The dehumidifier will cycle on and off to keep your selected setting until the 24 hours is over or the tank is full.
How Long Should a Dehumidifier Run Per Day?
The answer varies depending on many factors such as the room size and condition, as well as the unit’s capacity. In general, it’s best to run the dehumidifier for 6 to 12 hours a day or whenever the air is most humid during the day.
Depending on the room’s current condition, a dehumidifier may need to run for longer periods at a time if the place is extremely moist. For instance, basements with visible damp stains on the walls and floor may need a powerful dehumidifier running for the whole day to dry the moisture completely. In this case, make sure the unit has an auto shut-off feature that stops the operation when the collection bucket is full to avoid water overflow.
Alternatively, most dehumidifiers come with a gravity draining option so the water collected flows straight to your floor drain. If there is no available low-level drain in the room, some units also come with a drain pump that pushes the water out in any direction so you don’t need to raise the unit above the drain or sink. With either of these two drainage systems, you won’t need to worry about running your dehumidifier for a long period.
If operating the dehumidifier for the first time, give it a few hours before you can notice a significant change in humidity level. Once the ideal humidity is achieved, turn to a lower speed setting or simply shut off the unit. If the room is still humid after 12 to 24 hours of continuous operation, then there may be a different problem causing humidity. Find and fix the source of moisture immediately instead of running your dehumidifier nonstop to try to keep humidity levels down.
Disadvantages of Running A Dehumidifier Constantly
It isn’t wrong to leave your dehumidifier running constantly, but most of the time it is simply unnecessary. In extreme cases, it may do more harm than good.
Like any machine, your dehumidifier has a limited lifespan. Running the unit nonstop can’t be good for its longevity. It also needs to rest and cool down so it can function efficiently for a long time. Otherwise, it may cause the unit to overheat and lead to accidents.
You must also remember that running your dehumidifier consumes electricity and the longer it’s on the higher your bills. It also creates noise when operating and may be too loud and annoying when you’re trying to sleep at night.
Furthermore, continuous dehumidification may lower the relative humidity below the ideal range, which can be dangerous to your health. Low humidity can dry up your skin and eyes, irritate nasal airways and trigger cold and flu symptoms. Inhaling dry air can also increase the chance of upper respiratory infection.
While it’s usually not harmful to leave your dehumidifier running constantly, it will only shorten the unit’s life if you don’t remove the root cause of humidity.
Is it Safe to Leave a Dehumidifier on All Night?
In terms of electrical safety, yes, it’s safe to leave the dehumidifier running all night. However, there are a few factors you must consider to decide whether it’s best to do this.
Compressor dehumidifiers are naturally noisy when operating. The buzzing compressor noise can be disturbing but the fan sound can mask this and serve as white noise to help you sleep. Note that a larger dehumidifier usually makes more noise but it varies per brand and model. It’s important to check this if you want to use a dehumidifier at night.
Having a humidistat that maintains a set humidity level is essential to make sure the unit is not running unnecessarily when you sleep. Once you input your desired humidity level, the unit will work to achieve this then stop automatically until the humidity rises again.
If you’re using the collection bucket, make sure it’s large enough to hold the moisture removed throughout the night since you won’t be able to empty it. Or more conveniently, you can utilize continuous drainage so the unit will keep working as needed.
What Size Dehumidifier Do You Need?
The dehumidifier size or capacity is the total amount of moisture it can remove from the air in 24 hours, typically measured in pints per day or PPD. Standard household dehumidifiers now range from 20 to 50 pints in capacity. There are also smaller models below 20-pint capacity as well as even larger units 60 pints and higher.
It’s critical to find the correct dehumidifier size for your space to ensure it’s running efficiently. Two important factors that determine the right dehumidifier capacity are the room size and condition. We talk about this in greater detail in this article on dehumidifier sizing.
How Much Does It Cost to Run a Dehumidifier 24 Hours a Day?
The costs of operation depend mainly on the capacity of your unit. On average, dehumidifiers cost between $0.6 to $2.5 per 24 hours of continuous operation.
To estimate how much it costs to run your dehumidifier per hour, you need to know its power consumption measured in Watts (W) or kilowatts (kW). This is specified in the manual or on the unit itself. A 30-pint dehumidifier usually draws around 300-500 Watts, while a standard 50-pint draws 500-700 Watts, and mini Peltier dehumidifiers consume as low as 25 Watts.
You also need to know the rate of electricity in your area, which varies per state and utility company. The average rate of electricity in the US is around $0.13/kWh today. Using this, running a 500-Watt dehumidifier for 24 hours will cost around 0.5kW x $0.13/kWh x 24h = $1.56. Note that the actual amount of energy used changes depending on the setting.
To find out how efficiently your dehumidifier uses electricity, it’s also important to know the energy efficiency of the unit. Check the energy factor, in liters per kilowatt-hour (L/kWh), or look for the Energy Star label.
Alternatives To Running A Dehumidifier Constantly
Instead of letting your dehumidifier run constantly, you can follow these tips to help reduce indoor humidity.
Improve ventilation by opening windows and doors. Run your fans to let the air circulate, especially when you cook or after you take a shower. Also avoid hanging wet laundry indoors. Use a dryer or fan if needed. This helps keep the moisture and odors out.
If you can’t open the windows, run your air conditioner together with your dehumidifier to cool down the air and reduce humidity at the same time.
You may also try an alternative desiccant for a dehumidifier. Just put calcium chloride in a bucket or a large bowl and place it where it’s humid. You can even use natural moisture absorbers you’ll find in your kitchen such as rock salt and baking soda.
If you’ve done all these measures and you still have excess humidity, you need to look for the source. Check your plumbing, and fix any leaking pipes under sinks, in the bathroom, or in the basement.
When should I turn off my dehumidifier?
Ideally, a dehumidifier should be shut off once it reaches the optimal level. Maintain indoor humidity between 30% to 50% depending on the ambient temperature.
Do dehumidifiers turn off automatically?
Dehumidifiers with tanks have auto shut-off that activates when the tank is full to prevent water overflow. They also include a digital humidistat so the unit turns off automatically when your set humidity is reached.
Are dehumidifiers better in summer or winter?
Dehumidifiers can be useful in either summer or winter as long as the relative humidity is high. Although high temperatures typically come with higher humidity, you can always use a dehumidifier in winter if the humidity goes above 50%. Temperature and relative humidity control are both essential in maintaining your comfort.
How long does it take for a dehumidifier to work?
In most cases, you can notice a change in humidity within a few hours of running the dehumidifier. If used for the first time in a highly humid environment, it can take 12 to 24 hours to get the humidity down to your desired level, but it all depends on the size and condition of the space.