How Much Electricity Does a Dehumidifier Use?

How Much Electricity Does a Dehumidifier Use?

Ian Mutuli
Updated on
Ian Mutuli

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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Dehumidifiers as a household appliance play a crucial role of helping regulate indoor humidity levels. They also aid in the prevention of conditions that cause high humidity levels, such as mold, mildew, etc. However, the electricity consumption for dehumidifiers and how it affects electricity bills are some of the areas of concern for many people. Thus, our article aims to discuss the factors affecting the power consumption of a dehumidifier, how to estimate the energy consumption, and ways to reduce energy costs.

Let's get started!

What Is a Dehumidifier and How Does It Work

A dehumidifier can be defined as an electrical device that is used to remove excess moisture from the air of the room or any other confined area. The air dehumidifier serves to remove excessive moisture in the air which in some ways is good for wide ranging uses such as; enhancing air quality, discouraging formation of mold and mildew and promoting a favorable environment.

Dehumidifiers operate by removing moisture out of the air through a procedure known as condensation. Here's a general overview of how they work:

  1. Air intake: The dehumidifier draws damp air from the room through a vent or a grille.
  2. Cooling coils: The humid air from outside is condensed by passing through the cooling coils located at a lower temperature than that of the room. Consequently, the temperature of the air comes down.
  3. Condensation: Because the air is still warm, it cannot contain large amounts of water; the moisture starts to fall and form water droplets. These droplets then condense on the cooling coils or on a condensation coil within the dehumidifier.
  4. Drainage: The condensate water then drools or trickles into a bucket or a pan situated inside the dehumidifier. Some dehumidifiers come with a pump system that will discharge the water or you have to discharge the water on your own via a water tank.
  5. Air reheating: Once the air is dried, the dehumidifier warms up before discharging it back into the room. This helps to ensure that while the cooler air expelled by the de-humidifier is dry, the temperature of the room is not reduced.
  6. Humidity control: An additional feature that is found in most dehumidifiers is the humidity control knob that enables you to set the ideal humidity level that you want in the room. Once the set humidity level is achieved, the dehumidifier might stop working or switch into sleep mode until the humidity is high again.

Types of Dehumidifiers and Their Electricity Usage

Here is a general overview of the electricity usage for different types of dehumidifiers:

1. Refrigerative/Compressor Dehumidifiers

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These dehumidifiers compress the air with the help of a compressor and then pass it through a cooling cycle. The compressor uses a lot of electricity in compressing the refrigerant and in developing the required temperature gradient. The average power cost of refrigerative dehumidifiers can be as low as 300 watts for lower-capacity machines up to 1000 watts or more for high-capacity units.

2. Desiccant Dehumidifiers

Desiccant dehumidifiers rely on a wheel containing a desiccant material such as silica gel to remove water from the air. These dehumidifiers are typically cheaper and less energy-consuming than the ones that use a compressor. It is important to note that the desiccant dehumidifiers consumes power in the range of 200 – 500 watts depending on the size and control settings.

Desiccant dehumidifiers are especially effective in cooler climates since desiccant wheels do not use refrigeration. This means that they can continue to function at a low temperature which makes it ideal when placed in basements, garages or cold climate areas.

3. Ionic Membrane Dehumidifiers

Ionic membrane dehumidifiers uses a type of membrane that allows the moisture to pass through and not any other gaseous substances. These dehumidifiers are said to be very economical in terms of power consumption. Generally, depending on the model and the capacity of the lead-acid battery, they are known to draw rather moderate power which can be between 30 to 100 watts.

Ionic membrane dehumidifiers are recommended to be operated without noise and with low energy consumption. They are typically employed in residential areas or domestic uses because they do not require a lot of power.

4. Peltier Dehumidifiers

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Thermoelectric dehumidifiers or more commonly called Peltier dehumidifiers operate using the Peltier effect hence their name. These are usually small and more specialized for certain use, for example an area, a closet or even an RV.

Peltier dehumidifiers in general have relatively low power consumption levels, averaging between twenty to one hundred watts. However, they might be unable to draw moisture as effectively, which is why they are used primarily in localized areas or spaces that are less humid.

It is important to mention that the energy consumption mentioned above is calculated as approximate value depending on the actual make and model of the dehumidifier.

Calculating the Electricity Consumption of a Dehumidifier

Calculating the amount of electricity that is used in a dehumidifier requires the power rating and the time it uses. Here are the steps to estimate the energy consumption:

1. Identify the Power Rating:

The power rating of a dehumidifier is the electrical power it uses during its functioning, as stated by the power rating. It is rated in watts (W) or kilowatts (kW). The power rating is often indicated on the dehumidifier or is described in the user’s manual.

For instance you have a dehumidifier with a power rating of 800 watts (0. 8 KW). This is to mean that while the dehumidifier is working, it uses 800 watts of power in every one hour.

2. Determine the Usage Time:

To calculate the energy consumption, find out the number of hours or the range of time that the dehumidifier is used daily or monthly. This depends on factors such as the climate of the particular geographical locale, the level of humidity, and individual tendencies.

For example if you normally switch on the dehumidifier and operate it for eight hours every day then your usage time is eight hours.

3. Calculate Energy Consumption:

To estimate the energy consumption of your dehumidifier, follow these steps:

a. Convert the power rating to kilowatts (kW):

If the power rating is in watts (W), the value must be converted into kilowatts (kW) which is done by dividing the value by 1000. The power rating of 800 watts which in kilowatts can also be written as 0. 8 kW remains the same.

b. Multiply the power rating (in kW) by the usage time (in hours):

Take the power rating and convert it to kilowatts, then multiply it by the number of hours the appliance is used daily or monthly on average. Carrying on with the example, if dehumidifier has a power rating of 0. Peak power is 8 kW while the average usage is 8 hours in a day, the calculation will be 0. 8 kW / 1000 mA = 8 A; 8 kW × 8 hours = 6. 4 kilowatt-hours (kWh) per day.

c. Adjust for monthly usage:

To estimate the monthly energy consumption, one must multiply the daily energy consumption by the number of days in that particular month. If we take an example of 30 days in a month, this calculation would be 6. 4 kWh × 30 days = 192 kWh per month.

However, it is equally important to note that, above calculation gives approximate energy consumption of your dehumidifier by considering the power rating and usage time given above. They could be less depending on the efficiency of the device, how damp the surroundings are, and other aspects like features applied or settings changed.

Cost of Running a Dehumidifier

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To determine a dehumidifier energy cost, you need to consider the following factors:

  1. Among these factors, power consumption and the length of its use or operation time have been discussed above.
  2. Electricity cost: Check your electricity bill for the electricity price area per kilowatt-hour (kWh). This cost may differ depending on your location or the electricity company you are subscribed to. If you are unable to locate this information, you can use an approximate average of about $0. 12 per kWh in the United States

Once you have these values, you can use the following formula to calculate the cost of running your dehumidifier:

Cost per day = (Power rating in kilowatts) × (Operating hours per day) × (Electricity cost per kWh)

Cost per month = Cost per day × 30 (assuming a 30-day month)

Here's an example calculation:

Assuming the dehumidifier has a power rating of 0.5 kW, runs for 8 hours a day, and the electricity cost is $0.12 per kWh:

Cost per day = 0.5 kW × 8 hours × $0.12/kWh = $0.48

Cost per month = $0.48 × 30 = $14.40

Thus, the presumed expenditure of utilizing the dehumidifier in this example would be roughly $14. 40 monthly.

Just note that these calculations might be somewhat off as the electricity rates may differ, and the true power consumption of your dehumidifier can be slightly different from the nominal one.

Factors Influencing How Much Electricity a Dehumidifier Uses

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Just like any other electrical appliance, there are various causes that can affect the usage of electricity by a dehumidifier. Here are some of the key factors:

  1. Dehumidifier capacity: Some factors that have significant influence on the energy consumption of the dehumidifier include size or capacity of the dehumidifier. Larger models use more electricity than smaller models because they have to help remove humidity from a much larger area.
  2. Moisture levels: The moisture content present when the dehumidifier turns on together with the targeted level of humidity alters the duration and power consumption needed to achieve the set goal. With high levels of humidity in the air, some energy efficient models may take more time to operate and consume more power to get the optimal humidity.
  3. Room size: It is also noteworthy that energy consumption rate could depend on the size of the room or area that needs to be dehumidified. For a larger room, it would be necessary to install a more powerful dehumidifier, which will cost more in electricity.
  4. Energy efficiency rating: Search for higher energy efficiency rating dehumidifiers; some manufacturers denote this using Energy Star rating. Some of the best dehumidifiers with a built-in energy factor are those that consume least power as they work at removing the humidity in the air.
  5. Humidity settings: Another factor that influences energy consumption is the selected humidity level on the dehumidifier. Increased humidity levels mean that the dehumidifier is going to have to run for longer and use more electricity.
  6. Environmental conditions: Some of the environmental conditions that may affect the dehumidifier efficiency include the level of heat and humidity that is present in the environment. For instance, if one is using a dehumidifier, then it will consume more energy to reduce the humidity in warmer and humid climate.
  7. Usage patterns: The frequency and duration of using dehumidifier can also affect the energy usage. In the case where the dehumidifier is used for a longer period or is used frequently then it will use electricity.
  8. Maintenance: Some of the important steps in maintaining dehumidifiers involve cleaning the filter and coils, which helps to maximize its efficiency and effectiveness. A clogged small dehumidifier will require more efforts to operate hence will result in more energy being used.

Tips on Reducing How Much Energy a Dehumidifier Use

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Here are some tips to help reduce electricity usage when using a dehumidifier:

  1. Choose an energy-efficient dehumidifier: Today you can purchase Energy Star certified dehumidifiers because they are less energy-consuming while offering the same performance as the others.
  2. Proper sizing: Choose the correct capacity dehumidifier for the specific room or area that is to be dehumidified. If an air conditioner is oversized, it will use more power than necessary to cool the room and if it is under sized, it will have a hard time removing humidity from the air.
  3. Set the ideal humidity level: The majority of dehumidifiers have a control for programming the relative humidity you want in the room. Adjust it to a level that you find ideal (it is commonly between 40 and 50 percent). However, you should not set it too low as this will affect the runtime and power consumption levels.
  4. Location and ventilation: Ensure that the dehumidifier is positioned in a central area in the room it is placed in. Make sure it is not obstructed by furniture or any other material in the room in order to facilitate proper circulation of fresh air. Make sure to close the doors and windows to avoid the penetration of humid air into the space occupied by the dehumidifier.
  5. Regular maintenance: Clean the air filter regularly depending on the manufacturer’s instructions on how often the filter needs replacement. Dehumidifier filters need to be cleaned to enhance air flow, and when they are clogged, the device becomes less efficient and uses more electricity.
  6. Time and schedule usage: Some models come with timers or preprogrammed settings that allow the dehumidifier to operate only at certain intervals. For instance, you can let it operate at night when the prices of electricity are relatively low or when the humidity levels are high in a certain time of the day.
  7. Supplement with natural methods: As part of managing high humidity, consider using other methods in addition to running the dehumidifier. For instance, the use of ventilation fans, opening of windows during dry and cool periods, or the use of small packets of silica gel in closed compartments will help reduce the burden on the dehumidifier.
  8. Insulate the room: Proper insulation should also be carried out to make sure that excessive moisture does not infiltrate the room thus reducing the work load on the de humidifier. This is found in checking for leakages and sealing any crack and windows and doors should also be checked out for proper insulation. 

Frequently Asked Questions on How Much Electricity Does a Dehumidifier Use

a) Which is cheaper to run a dehumidifier or air conditioner?

The cost of electricity in most energy-efficient dehumidifiers when compared with air conditioners depends on the energy efficiency of each unit, size of the area being conditioned or dehumidified, local climate and duration of the process.

Air conditioners are mainly expected to cool the air besides minimizing humidity levels in the room. For instance, if a room requires both cooling and dehumidification, an air conditioner can perform both functions, thus being more efficient than having to use two appliances. However, a dehumidifier will be more efficient and cheaper if you only require to remove moisture from the air without the need for cooling.

In general, dehumidifiers are less bulky and use less energy compared to air conditioners. Their primary use is to reduce humidity levels within homes which may greatly improve indoor air quality and promote mould and mildew. Thus, the best bathroom dehumidifier is usually more cost-effective if your primary goal is to eliminate moisture.

Ian Mutuli

About the author

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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