Dehumidifier

What Is a Dehumidifier? Functions, Types, Sizes, Costs, Installation and Maintenance

Nayeem Ibnay Zaman

Table of Contents

A dehumidifier removes excess moisture from indoor air, maintains balanced humidity, prevents mold and odors, protects against damage and creates a healthier or comfortable environment. It works by pulling in damp air, extracting moisture through condensation or absorption and releasing drier air to keep humidity levels between 30% and 50%. Dehumidifier types include refrigerant dehumidifier models for larger, humid spaces, desiccant units suited for cooler areas, and thermoelectric options ideal for small, enclosed spaces.

Dehumidifier comes in multiple sizes like 22, 50 and 70 pint units, designed to serve rooms ranging from 300 to 4,400 square feet. Dehumidifiers cost about $1 to $2 per day or $30 to $60 per month to operate, with Energy Star designs lowering energy expenses. It helps with allergy relief, odor control, mold prevention, property protection, easier breathing, insect deterrence, food preservation and comfort improvement, which makes it valuable for homes and businesses.

A dehumidifier installation involves proper placement, safe drainage setup, plugging into a grounded outlet and setting the desired humidity. It requires central positioning, closed windows, regular water disposal and filter cleaning. Dehumidifier maintenance involves sanitizing the tank, checking hoses and coils, repairing worn parts, and arranging annual professional inspections. This confirms optimal performance and longevity of a dehumidifier while keeping indoor air fresh.

What is a dehumidifier?

A dehumidifier is an electrical appliance designed to reduce and maintain the level of humidity in indoor spaces. It helps create a healthier and more comfortable environment by preventing excess moisture, which causes mold growth, musty odors and damage to furniture or walls.

What does a dehumidifier do?

A dehumidifier removes excess moisture from the air to lower indoor humidity levels and create a comfortable, healthier environment. It accomplishes this by pulling in damp air, condensing the moisture into water droplets and releasing drier air back into the room. A dehumidifier helps prevent mold, mildew and dust mite growth because it lowers excess moisture in the air. It reduces musty odors by keeping indoor humidity balanced and protects items such as wooden furniture, painted walls and electronic devices from damage caused by dampness.

How does a dehumidifier work?

A dehumidifier works by drawing in humid air, extracting moisture through condensation or absorption and releasing drier air into the room that helps prevent mold, allergens and excess indoor moisture.

5 steps of how a dehumidifier works are given below.

  1. Air Intake: A dehumidifier draws humid air into the unit through its intake vent using a fan.
  2. Extracting Moisture: A dehumidifier channels the incoming air over a cooling coil or desiccant material, which depends on the unit type.
  3. Condensation (refrigerant based): A dehumidifier utilizes chilled coils to cause airborne water vapor to condense, which forms water droplets that collect in a tank. This process is known as dehumidifier condensation.
  4. Absorption (desiccant based): Desiccant dehumidifiers employ materials like silica gel to capture moisture from the air by absorption instead of condensation.
  5. Air output: A dehumidifier returns drier air to the room, which maintains comfortable humidity and protects against mold and allergens.

 

A dehumidifier works through these steps to remove excess moisture, safeguard indoor air quality and minimize problems associated with high humidity.

The image below explains how a desiccant dehumidifier works by showing humid air passing through a rotating desiccant wheel to produce dry air while a heated reactivation airflow removes absorbed moisture.

What are the different types of dehumidifiers?

The different types of dehumidifiers are refrigerant (compressor), desiccant and thermoelectric models. These dehumidifiers either condense water vapor or absorb moisture from the air. Refrigerant dehumidifiers work well in living rooms and basements, while desiccant units perform better in damp bathrooms or cooler climates.

3 different types of dehumidifiers are given below.

  1. Refrigerant (compressor) dehumidifiers: Refrigerant (compressor) dehumidifiers use a cooling system to condense water vapor from the air onto cold coils and collect liquid in a tank. They work well for larger areas with high humidity integrated into the HVAC system.
  2. Desiccant dehumidifiers: Desiccant dehumidifiers absorb moisture from the air using a desiccant material and expel it through heating. A desiccant system is very efficient in cooler temperatures and is suitable for unheated spaces like crawl spaces or garages.
  3. Thermoelectric (Peltier) dehumidifiers: Thermoelectric dehumidifiers employ the Peltier effect to condense water vapor onto a cold plate. Thermoelectric models are compact, quiet and best for small environments like cabinets to lower humidity without complex mechanisms such as fan compressors, cooling coils and reheaters.

 

The image below presents a comparison table of refrigerant, desiccant, and thermo-electric dehumidifiers, outlining how they work, their ideal climate, efficiency, noise level, moisture removal capacity, and best use cases.

You can choose the best option for your space and requirements, as these types of dehumidifiers offer distinct mechanisms, capacities and operating advantages that allow effective moisture control for various room sizes and climates.

What are the available sizes of dehumidifiers?

The available sizes of dehumidifiers range from mini to extra large, each designed for specific spaces and moisture levels. They vary in capacity from removing 1 to 100 pints of moisture daily, suitable for areas from 200 to over 2,600 square feet.

The available sizes of dehumidifiers are outlined below.

  • Mini dehumidifiers: Mini dehumidifiers are ideal for spaces around 200 square feet, remove 1 to 4 pints per day and suit mildly damp rooms.
  • Small dehumidifiers: Small dehumidifiers suitable for 200 to 400 square feet areas, remove 5 to 20 pints per day and work well for bedrooms or closets.
  • Medium dehumidifiers: Medium dehumidifiers are designed for 20 to 800 square feet rooms, remove 21 to 40 pints daily and serve moderate moisture needs.
  • Large dehumidifiers: Large dehumidifiers are suited for 600 to 1,200 square feet spaces, remove 41 to 60 pints per day and are perfect for bigger or damp basements.
  • Extra Large dehumidifiers: Extra large dehumidifiers meant for 800 to over 2,600 square feet, remove 61 to 100  pints each day and handle commercial or flood prone sites.

The average dehumidifier sizes by room size are shown below.

How much does it cost to run a dehumidifier?

A dehumidifier costs $1 to $2 per day to operate, for an average 50 pint unit running 8 hours a day in the US, according to research from the Greenwashing Index. A dehumidifier cost adds up to about $30 to $60 per month, which results in costs ranging from $360 to $700 annually.  It depends on system size, efficiency, usage pattern, humidity level and local electricity rates. A large dehumidifier in a high electricity rate area increases the cost, while choosing an Energy Star model reduces the cost to run a dehumidifier up to 13% to 15%.

What are the benefits of dehumidifiers?

The benefits of dehumidifiers are creating a healthier indoor environment by lowering humidity, reducing allergens and protecting home surfaces and belongings from moisture related damage.

The benefits of dehumidifiers are given below.

  • Allergy reduction: Dehumidifiers reduce airborne allergens such as mold, dust mites. and pollen that lower symptoms like coughing, sneezing and irritation for allergy prone individuals in humid spaces.
  • Odor elimination: Dehumidifiers prevent musty odors caused by mold and mildew in damp rooms that keep indoor air fresh and pleasant throughout the year.
  • Mold and mildew prevention: Dehumidifiers inhibit the growth of mold and mildew on walls, windows and fabric by maintaining optimum humidity and controlling condensation.
  • Property protection: Dehumidifiers help preserve furniture, electronics and valuables from moisture damage, rust and warping, which extend their usability and appearance.
  • Asthma and respiratory support: Dehumidifiers improve comfort for asthma sufferers by lowering humidity, which makes breathing easier and reduces respiratory irritation.
  • Comfort enhancement: Dehumidifiers create a cooler feel in summer and reduce clamminess that promotes balanced room temperatures and contributes to reduced cooling costs such as air conditioning bills or electricity usage.
  • Insect deterrence: Dehumidifiers reduce populations of insects such as cockroaches, silverfish and spiders that thrive in moist environments like basements or bathrooms.
  • Food preservation: Dehumidifiers help food items like chips and snacks stay crisp and fresh longer by reducing excess moisture in the air.

 

The image highlights the benefits of using a dehumidifier in a bedroom, including reduced humidity, better sleep comfort, fewer allergens, mold prevention, fresher air, and protection of furniture and walls.

How to install a dehumidifier?

To install a dehumidifier, position the unit in a suitable location, connect it to a grounded electrical outlet, set your desired humidity level and ensure continuous drainage using a hose while avoiding obstructions and sources of moisture. Whole house dehumidifiers require professional installation because of their complexity.

6 steps to install a dehumidifier are given below.

  1. Choose locations: Select a stable spot away from walls or obstructions and potential sources of moisture. Position the dehumidifier for maximum airflow, filter access and safety near a grounded electrical outlet.
  2. Prepare for drainage: Attach a hose to the dehumidifier for continuous drainage and route it to a drain or sink to prevent water buildup. Ensure the hose slopes downward to allow proper water flow and avoid leaks.
  3. Plug into grounded electrical outlet: Connect the dehumidifier securely to a grounded outlet that matches the manufacturer’s power specifications such as 120V AC, 1-phase and 240W rated consumption. Confirm the cord is not stretched or exposed to moisture to minimize electrical risks like a damaged power cord or overloaded circuit.
  4. Set desired humidity level: Adjust the humidistat or control panel to your desired humidity level between 30 to 50%. Monitor the display of the dehumidifier and adjust as needed for comfort and moisture control in your room.
  5. Test and monitor performance: Power up the dehumidifier and check that airflow and operating sounds are consistent. Make sure it is collecting water and the controls work properly. Review humidity levels on the display and adjust settings as necessary for effective performance.
  6. Maintain regularly: Clean air filters of the dehumidifier and inspect for blockages or leaks monthly. Wipe down exterior surfaces and check that the hose for continuous drainage remains clear for optimal lifespan and air quality.

You get the best results from a dehumidifier when proper dehumidifier installation and regular maintenance are in place. This confirms reliable performance, air quality and long term safety that helps you create a more comfortable environment.

How to use a dehumidifier?

To use a dehumidifier, place it in a central location for optimal airflow, set your preferred humidity level, keep doors and windows closed, manage water disposal and clean filters regularly to confirm effective and long lasting performance.

Tips to use a dehumidifier are outlined below.

  • Position the dehumidifier: Set your dehumidifier in a central spot away from walls and furniture. This allows for good air circulation, improves moisture removal and prevents blockages for maintenance.
  • Set your desired humidity: Adjust the control panel of your dehumidifier to a range of 30 to 50%. Check humidity levels using the built in display or a hygrometer and fine tune settings for ideal comfort and mold prevention.
  • Keep windows and doors closed: Confirm windows and doors remain shut during dehumidifier operation. This prevents humid air from entering the space, which makes the unit work efficiently and achieve quicker results.
  • Water disposal: Check the water tank of your dehumidifier regularly and empty it as needed. Connect a drain hose if the option is available for continuous water removal to avoid overflows and maintain safe, uninterrupted performance.
  • Maintain and clean regularly: Clean the filter and air inlets every month to keep the dehumidifier functioning properly, extend its lifespan and maximize its moisture control benefits like less mold and mildew.

How to maintain a dehumidifier?

To maintain a dehumidifier, regularly clean the filter, empty and sanitize the water tank, check all components for damage or blockages and conduct periodic inspections for reliable long term performance.

The steps to maintain a dehumidifier are given below.

  • Clean the air filter: Remove the air filter of the dehumidifier monthly and rinse it with water to prevent dust buildup, maintain airflow and keep the device working efficiently.
  • Empty and sanitize the tank: Always empty the dehumidifier water tank when full and clean it with mild soap every week. This avoids mold, odors and water related issues inside the reservoir.
  • Inspect coils and hoses: Check coils and connected hoses for dust, debris or blockages in the dehumidifier. Clean as needed to preserve moisture removal efficiency and prevent leaks or clogs.
  • Check for damages: Inspect the dehumidifier for cracks, worn electrical cords and loose fittings during routine checks. Repair or replace any damaged parts like the compressor, fan motor and humidistat to prevent electrical hazards and support a longer dehumidifier lifespan.
  • Schedule periodic inspection: Arrange an annual professional inspection to confirm safe operation, detect potential issues such as leaks or faulty wiring and verify that the dehumidifier provides consistent performance each year.


You can maintain a dehumidifier with these simple steps that help confirm reliable performance, extended lifespan and consistent moisture control for a healthier indoor space.

How often should you clean a dehumidifier?

You should clean a dehumidifier every two to three weeks during frequent use periods. Its cleaning frequency depends on factors such as how long the dehumidifier runs, the humidity level of the house, the amount of household dust and the size of the water collection tank. Dehumidifier regular cleaning helps prevent mold, maintain efficiency and extend the unit’s lifespan.

How do you know if a dehumidifier is working?

Things to check to know if a dehumidifier is working are given below.

  • Check the dehumidifier’s performance by confirming that the water tank fills or the drain hose releases water regularly.
  • Measure the humidity level in the room with a hygrometer and confirm a reduction after running the dehumidifier for several hours.
  • Listen for consistent compressor and fan noise because this sound shows the dehumidifier is working normally without faults.
  • Check for cold coils inside the dehumidifier, as working units produce cold coils when removing moisture from the airflow.
  • Confirm the desired humidity setpoint is reached on the control panel and verify power with indicator lights to check the dehumidifier’s performance.

Why do dehumidifiers stop working?

A dehumidifier stops working because of the power supply, blocked airflow, low room temperature or refrigerant leaks. Its common problems include the unit’s internal components failing, clogged filters restricting airflow, full water tanks stopping operation and frozen coils caused by cold temperatures.

When to use a dehumidifier?

You need to use a dehumidifier when indoor humidity consistently stays above 50 to 55%, as excess moisture creates an unhealthy environment. It becomes necessary when you notice home conditions such as a sticky, musty atmosphere, visible mold or mildew, condensation on windows, a persistent damp smell and an increase in insect activity. These conditions are common signs to use a dehumidifier to achieve a healthier humidity balance and improve comfort in your home.

Does a dehumidifier help with mold?

Yes, a dehumidifier helps with mold because it controls excess moisture that creates favorable conditions for spores to spread. It reduces dampness by lowering the indoor humidity level, which limits fungal growth. A dehumidifier helps prevent mold by keeping moisture within safe ranges like 30 to 50% which makes it easier to manage mold growth effectively in enclosed spaces such as basements, crawlspaces and bathrooms.

Does a dehumidifier cool a room?

No, a dehumidifier does not cool a room because it does not lower the air temperature. A dehumidifier impacts cooling a room by reducing humidity that helps sweat evaporate more efficiently, which makes the space feel cooler and more comfortable. It allows you to raise the thermostat a few degrees while still feeling comfortable by lowering the moisture in the air, which creates a cooling sensation without decreasing the temperature.

Do dehumidifiers use a lot of electricity?

No, dehumidifiers do not use a lot of electricity because their power demand is relatively moderate. Dehumidifiers’ electricity use depends on their size and efficiency. Their average electricity usage is around 500W per hour, which is less than appliances like an air conditioner, washing machine or clothes dryer.

Are dehumidifiers safe for pets?

Yes, dehumidifiers are safe for pets because they improve indoor air quality without releasing harmful substances such as chemicals, fumes or toxic gases. They help reduce humidity, alleviate respiratory issues like coughing, sneezing or nasal congestion and limit mold, mildew or allergens, which make dehumidifiers safe for pets. Dehumidifiers benefit pets by preventing skin irritation, reducing heat stress, and creating a healthier living space.

How long do dehumidifiers last?

Dehumidifiers last about 5 to 10 years, which depends on the model, usage frequency, maintenance habits and environmental factors. Portable dehumidifiers last 3 to 5 years with heavy use, while well maintained crawl space and commercial dehumidifiers’ lifespan reaches 8 to 10 years or longer. Whole house dehumidifiers last between 10 and 20 years if properly maintained.

Are dehumidifiers worth it?

Yes, dehumidifiers are worth it because they help prevent moisture damage and improve comfort in homes with high humidity. Dehumidifiers are especially valuable for individuals with allergies or asthma, as they reduce mold and dust mite levels. Dehumidifiers are worth the investment for keeping the air dry, reducing energy costs, and promoting healthier indoor living.

What are the pros and cons of a whole house dehumidifier?

The pros and cons of a whole house dehumidifier are given in the table below.

 

Pros of a whole house dehumidifier

Cons of a whole house dehumidifier

Reduces humidity and improves comfort.

Higher upfront installation cost.

Improves indoor air quality.

Higher energy usage.

Prevents mold and mildew growth.

Needs professional installation.

Extends HVAC system lifespan.

Fixed, not portable.

Low maintenance with automatic drainage.

Not needed for small homes.


The pros and cons of a whole house dehumidifier highlight improved comfort and air quality versus higher costs and installation requirements for effective humidity control.

What are the top dehumidifier brands?

5 best dehumidifier brands are given below.

  1. Midea offers high quality dehumidifier models with smart features and strong warranties.
  2. Frigidaire is a consistent best seller known for reliability and powerful moisture removal.
  3. Honeywell features durable units with advanced controls and long lasting performance.
  4. hOmeLabs provides affordable, efficient and user friendly portable dehumidifiers.
  5. Meaco delivers energy efficient products, popular for quiet operation and sleek design.

Which is the best dehumidifier?

Midea Cube (MAD50S1QWT) is considered one of the best dehumidifiers because it is the fastest at reducing room humidity and features the largest water tank among its competitors. This efficient design allows the dehumidifier to operate longer between emptying cycles, which makes it a top choice for managing moisture in larger spaces.

What is the difference between a dehumidifier and a humidifier?

A dehumidifier removes moisture from the air to reduce excessive humidity that helps to prevent mold and dampness. A humidifier, on the other hand, adds moisture to the air to combat dry air and associated discomfort. This fundamental contrast defines a dehumidifier versus a humidifier in managing indoor air quality.

What is the difference between a dehumidifier and an air purifier?

The difference between a dehumidifier and an air purifier is their main function. A dehumidifier removes excess moisture from the air to help prevent mold and dampness, while an air purifier removes airborne particles and pollutants that tackle allergens to improve air quality and reduce respiratory issues like asthma or chronic bronchitis.

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