Dehumidifier vs Humidifier Illustration Explained

Humidifier vs. Dehumidifier: What’s the Difference? (2024)

by | Updated: Apr 19, 2024

Humidifiers and dehumidifiers are essential appliances that play a crucial role in maintaining optimal indoor air quality and comfort.

While both devices are designed to regulate humidity levels in a room, they serve distinctly different purposes.

A humidifier adds moisture to the air to alleviate dryness, often used during cold or arid conditions, while a dehumidifier removes excess moisture from the air to prevent dampness and mold growth, which is beneficial in humid climates or during wet seasons.

Understanding the difference between these two appliances is vital for selecting the right solution for your specific needs, ensuring a comfortable and healthy living environment.

What is a Humidifier?

A humidifier is an appliance designed to increase the humidity, or moisture content, in the air within a room or an enclosed space. By adding moisture to the air, humidifiers help alleviate dryness, which can cause discomfort or health issues such as dry skin, irritated eyes, sore throat, and respiratory problems.

They are particularly useful during colder months or in arid environments when indoor air can become excessively dry due to heating systems or low outdoor humidity.

There are various types of humidifiers, including ultrasonic, evaporative, steam vaporizer, and impeller models. Each type works differently, but their primary function remains the same: to release moisture into the air, thereby improving indoor air quality and comfort.

Humidifiers can be standalone devices or integrated into an HVAC system, depending on the desired coverage area and individual needs.

Proper use and maintenance, such as regular cleaning and monitoring humidity levels, are crucial to ensure the device’s effectiveness and prevent potential issues like mold or bacteria growth.

Best Humidifier for Home Use

The Everlasting Comfort Ultrasonic Cool Mist Humidifier stands out as the best choice due to its impressive features and performance.

With a large 6-liter water tank, it can operate continuously for up to 50 hours, providing consistent and adjustable cool mist output for maximum comfort.

Additionally, its built-in essential oil tray and whisper-quiet operation further enhance the user experience, making it an ideal option for maintaining optimal humidity levels in any living space.

Our Top Pick
Everlasting Comfort Ultrasonic Cool Mist Humidifier

A high-quality cool mist humidifier for improved wellness, comfort, and breathing in your home.

If you click this link and make a purchase, we earn a commission at no additional cost to you.

What is a Dehumidifier?

A dehumidifier is an appliance designed to reduce and maintain the humidity levels in the air within a room or an enclosed space by removing excess moisture. High humidity can lead to discomfort, musty odors and facilitate the growth of mold, mildew, and dust mites, which can cause health issues, especially for those with allergies or respiratory problems.

Dehumidifiers are particularly beneficial in humid climates, damp basements, or during wet seasons when indoor air tends to retain excessive moisture.

Dehumidifiers work by drawing in moist air, cooling it down to condense the moisture into water, and then releasing the drier air back into the room. The collected water is either stored in a tank that needs to be emptied periodically or drained continuously through a hose.

There are several types of dehumidifiers, including refrigerant, desiccant, and whole-house models. The choice of a dehumidifier depends on factors like the size of the space, the level of humidity, and individual preferences.

Regular maintenance, such as cleaning filters and ensuring proper drainage, is essential for the efficient operation of a dehumidifier.

Best Dehumidifier for Home Use

The hOmeLabs 4,500 Sq. Ft Energy Star Dehumidifier is a top choice due to its powerful performance and energy efficiency.

Capable of removing up to 50 pints of moisture per day, it effectively covers large spaces up to 4,500 square feet, making it ideal for basements, living areas, or entire homes.

The Energy Star certification ensures environmentally friendly operation, reducing energy consumption without compromising on performance, making it an excellent investment for maintaining optimal indoor air quality.

Best Overall
HomeLabs 4,500 Sq. Ft Energy Star Dehumidifier

Delivers powerful moisture removal and energy-efficient operation, making it perfect for large spaces and promoting a comfortable, healthy living environment. 

If you click this link and make a purchase, we earn a commission at no additional cost to you.

What is the Difference Between a Humidifier and a Dehumidifier?

The primary difference between a humidifier and a dehumidifier lies in their functions: a humidifier increases humidity levels by adding moisture to the air, while a dehumidifier reduces humidity levels by removing excess moisture from the air, addressing opposing concerns related to air quality and comfort in indoor environments.

A humidifier and a dehumidifier are designed to address different humidity-related issues in an indoor environment by performing opposing tasks:

  • Function: A humidifier increases the moisture content in the air by releasing water vapor or mist, which helps alleviate dryness and improves overall comfort. On the other hand, a dehumidifier removes excess moisture from the air by drawing in humid air, condensing the moisture into water, and then releasing the drier air back into the room. This process helps maintain a balanced humidity level and prevents problems associated with excessive moisture.
  • Purpose: Humidifiers are typically used in colder months or arid climates when indoor air tends to become excessively dry due to heating systems or low outdoor humidity. They help alleviate symptoms of dry skin, irritated eyes, sore throat, and respiratory issues. Dehumidifiers, in contrast, are more beneficial in humid climates, damp basements, or during wet seasons when indoor air retains too much moisture, leading to musty odors, mold growth, and an increase in allergens.
  • Types: Different types of humidifiers include ultrasonic, evaporative, steam vaporizer, and impeller models. Each works in a unique way to release moisture into the air. Dehumidifiers, on the other hand, come in refrigerant, desiccant, and whole-house models, with variations in size and capacity to cater to individual needs and preferences.
  • Maintenance: Humidifiers require regular cleaning to prevent mold and bacteria growth, as well as monitoring of humidity levels to avoid excessive moisture. Dehumidifiers need maintenance that includes cleaning filters, ensuring proper drainage, and monitoring humidity levels to maintain a healthy and comfortable living environment.

While both humidifiers and dehumidifiers regulate humidity levels, their main difference lies in whether they add or remove moisture from the air to address specific concerns related to air quality, comfort, and health in indoor spaces.

Humidifier vs Dehumidifier Vector Illustration Graphic

Problems Indicating the Need for a Humidifier or a Dehumidifier

There are several problems that may indicate the need for a humidifier or a dehumidifier in your home.

Being aware of these signs can help you address humidity imbalances and maintain a comfortable and healthy living environment.

Humidifier Indications

  • Dry skin, chapped lips, and itchy eyes: Low humidity levels can cause your skin to become dry and irritated, leading to itching, flaking, and chapped lips. It can also cause discomfort and dryness in your eyes.
  • Respiratory issues: Dry air can irritate the respiratory system, causing sore throat, nasal congestion, and exacerbating asthma or allergy symptoms.
  • Static electricity: Excessively dry air can lead to an increase in static electricity, which can be annoying and potentially harmful to sensitive electronic devices.
  • Cracking wood: Low humidity levels can cause wooden furniture, floors, and instruments to dry out, leading to cracks and other damage.
  • Peeling wallpaper or paint: Dry air can cause the wallpaper or paint in your home to peel or crack.

Dehumidifier Indications

  • Mold and mildew growth: High humidity levels create an ideal environment for mold and mildew to grow, which can cause health issues and damage to your home.
  • Musty odors: Excess moisture can lead to unpleasant, musty smells that indicate the presence of mold or mildew.
  • Condensation on windows: If you notice condensation on your windows or other cold surfaces, it is a sign of excessive humidity levels in your home.
  • Allergy symptoms: High humidity levels can aggravate allergies by promoting the growth of allergens like mold, mildew, and dust mites.
  • Dampness and water damage: Excessive humidity can cause dampness in your home, leading to water damage, staining, and rot in walls, ceilings, and floors.

Note: If you observe any of these issues in your home, it may be time to invest in a humidifier or a dehumidifier to regulate humidity levels and maintain a comfortable and healthy living environment. Regularly monitoring humidity levels can also help you make informed decisions about when to use these appliances.

How to Measure Humidity in Your Home

Measuring humidity in your home is essential for maintaining a comfortable and healthy living environment. The most accurate and common way to measure humidity is by using a hygrometer, also known as a humidity meter or a relative humidity sensor.

These devices measure the percentage of relative humidity in the air. There are digital and analog hygrometers available, with digital models generally offering better accuracy and additional features, such as temperature readings.

Best Overall
ThermoPro TP50 Digital Indoor Hygrometer

An accurate and user-friendly device designed to measure indoor temperature and humidity levels, helping you maintain optimal living conditions in your home.

If you click this link and make a purchase, we earn a commission at no additional cost to you.

To use a hygrometer, place it in the room where you want to measure humidity, and allow it to acclimate for a few hours before reading the results.

For a comprehensive understanding of your home’s humidity levels, place hygrometers in multiple rooms and check the readings regularly.

How to Maintain Optimal Indoor Humidity Levels

To maintain optimal indoor humidity levels, it is recommended to keep the relative humidity between 30% and 50%. If your home’s humidity levels fall outside this range, consider using a humidifier or dehumidifier to achieve a more comfortable and healthy environment.

Regularly monitoring humidity levels will help you make necessary adjustments and ensure the well-being of your living space.

FAQs About Humidifiers and Dehumidifiers

Do I Need a Humidifier or a Dehumidifier?

Determining whether you need a humidifier or a dehumidifier depends on the humidity levels in your home and the problems you are experiencing.

If you notice signs of low humidity, such as dry skin, respiratory issues, or static electricity, a humidifier might be necessary.

On the other hand, if you experience issues related to high humidity, such as mold growth, musty odors, or condensation on windows, a dehumidifier would be more appropriate.

Regularly monitoring humidity levels with a hygrometer can help you decide which appliance is best for your situation.

How Does Humidity Affect Your Home?

Humidity affects your home in various ways, impacting both the comfort and the overall health of the living environment.

High humidity levels can lead to mold and mildew growth, musty odors, increased allergens, and structural damage due to dampness.

On the other hand, low humidity can cause dry skin, respiratory problems, increased static electricity, and damage to wooden furniture or instruments.

Maintaining balanced humidity levels between 30% and 50% ensures a comfortable and healthy living space.

How Does the Weather Affect Indoor Humidity?

Weather conditions play a significant role in affecting indoor humidity levels. During cold or dry seasons, the outdoor air holds less moisture, which can lead to lower indoor humidity levels, especially when using heating systems.

In contrast, humid climates or wet seasons can cause an increase in indoor humidity levels as the outdoor air holds more moisture.

The use of air conditioning, ventilation systems, and weather-sealing techniques can help mitigate the impact of weather on indoor humidity.

However, using a humidifier or a dehumidifier may be necessary to maintain optimal humidity levels in your home, depending on the specific conditions.

Why Is Your Dehumidifier Not Agreeing with Your Humidity Meter?

There may be discrepancies between the humidity reading on your dehumidifier and that of an external humidity meter (hygrometer) for several reasons:

  • Calibration: Both the dehumidifier and the hygrometer may have different calibration settings, leading to slight variations in readings.
  • Sensor quality: The quality and accuracy of the humidity sensors in the dehumidifier and the hygrometer can differ, resulting in discrepancies.
  • Location: The humidity levels can vary within different areas of the room, so placing the dehumidifier and hygrometer in separate locations can cause discrepancies in readings.

To ensure accurate humidity measurement, use a reliable hygrometer, place it near the dehumidifier, and allow some time for the readings to stabilize.

How Does a Dehumidifier Actually Measure the Room Conditions?

A dehumidifier typically uses a built-in humidity sensor (hygrometer) to measure the room’s relative humidity. These sensors work by detecting changes in electrical resistance or capacitance due to moisture in the air.

When the humidity sensor detects a humidity level higher than the user-defined setting, the dehumidifier will turn on to remove excess moisture from the air.

Once the desired humidity level is reached, the dehumidifier will turn off automatically.

Can You Install Both a Humidifier and Dehumidifier in Your Home?

Yes, you can install both a humidifier and a dehumidifier in your home, but it is essential to use them in the appropriate situations and in different areas or rooms of the house.

A humidifier is suitable for use in dry conditions, while a dehumidifier is needed for damp or high-humidity environments.

Using both appliances simultaneously in the same room may create a cycle of adding and removing moisture, which is inefficient and counterproductive.

Final Thoughts

Both humidifiers and dehumidifiers play significant roles in creating a comfortable and healthy living environment by addressing different humidity-related issues.

Understanding the differences between these two appliances, their specific functions, and the various types available is essential for selecting the most suitable option for your needs.

By incorporating the right device and performing regular maintenance, you can effectively maintain optimal indoor air quality, reduce potential health risks, and enjoy a more comfortable living space tailored to your specific climate and personal preferences.

John Landry, BS, RRT

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.


  • Byber, Katarzyna et al. “Humidification of indoor air for preventing or reducing dryness symptoms or upper respiratory infections in educational settings and at the workplace.” The Cochrane database of systematic reviews vol. 12,12 CD012219. 10 Dec. 2021.
  • Custovic, A et al. “Portable dehumidifiers in the control of house dust mites and mite allergens.” Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology vol. 25,4 (1995).
  • Chen, Ling-Hsi, and Chiachung Chen. “Uncertainly Analysis of Two Types of Humidity Sensors by a Humidity Generator with a Divided-Flow System.” Sensors (Basel, Switzerland) vol. 18,2 637. 21 Feb. 2018.
  • “Mold Course Chapter 2: | US EPA.” US EPA, 6 July 2022.

Recommended Reading