When to Use a Dehumidifier: Winter or Summer?

By: Evan Scoboria, Last updated: June 28, 2023

When to use a dehumidifier can often seem like a puzzle. While most homeowners understand these devices are essential for managing indoor humidity, knowing when to use them can be challenging. Is running a dehumidifier during hot, humid summers or cold, potentially damp winters best? This article aims to dispel your doubts by examining the factors that impact indoor humidity levels across seasons. By understanding these factors, you can determine the optimal time for running a dehumidifier in your home, enhancing comfort and maintaining a healthy indoor environment.

Humidity Levels in Summer

During summer, humidity levels outside and inside your home typically rise due to warmer temperatures. The warmer the air, the more moisture it can hold, which results in higher humidity levels.

When indoor humidity exceeds 50%, it can cause problems in your home. These can include:

  1. Increased Mold and Mildew Growth: High humidity creates an ideal environment for mold and mildew to grow, particularly in damp areas of your home like bathrooms, basements, and kitchens.

  2. Musty Odors: Excess moisture in your home can lead to musty odors, often associated with mold and mildew growth.

  3. Increased Allergens: Dust mites, a typical indoor allergen, thrive in high-humidity environments. This can worsen allergies and asthma symptoms for individuals who are sensitive to these allergens.

  4. Discomfort and Excessive Sweating: High humidity can make your home sticky and uncomfortable. It can also make your body feel warmer than it is, leading to excessive sweating.

  5. Increased Energy Usage: High humidity can make your air conditioning system work harder to cool your home. This is because the extra moisture in the air makes it feel warmer than it is, causing your AC to run more frequently and consume more energy.

Using a dehumidifier during the summer can help manage these issues by removing excess moisture from the air, thereby reducing humidity levels to a more comfortable range (between 30% and 50%). This can prevent mold and mildew growth, reduce allergens, make your home feel cooler, and save energy costs.

Humidity Levels in Winter

In contrast to summer, winter is generally characterized by colder and drier air. However, indoor humidity levels can still become elevated during the winter months due to various factors.

The colder air holds less moisture than warm air, so when the cold air enters your home and is warmed by your heating system, its relative humidity decreases because warm air can hold more moisture. However, everyday activities such as cooking, showering, or even breathing can add moisture to the air inside your home, raising indoor humidity levels.

In addition, many homes are sealed tightly against the winter cold, which can prevent moisture from escaping and lead to increased indoor humidity. Poor ventilation, insufficient insulation, and lack of proper air circulation can also contribute to higher humidity levels in winter.

Excess humidity in winter can lead to several problems:

  1. Condensation on Windows: When warm, humid air comes in contact with the cold glass of a window, it cools down and releases some of its moisture as water, leading to condensation. This can be an indication of high indoor humidity.

  2. Mold Growth: Even in winter, if the humidity levels are high, mold can grow in your home, especially in areas like bathrooms and basements where humidity tends to be higher.

  3. Damage to Home Structures: High humidity can lead to moisture damage in your home, including warping wood, peeling paint, and damage to insulation.

  4. Health Issues: High indoor humidity can also trigger allergy symptoms and respiratory issues due to increased allergens like mold and dust mites.

Despite these potential issues, it's essential to be careful when using a dehumidifier during winter. Over-dehumidifying can lead to too dry air, which can cause dry skin, irritated sinuses, static electricity, and discomfort. As such, it's essential to regularly monitor indoor humidity levels and adjust your dehumidifier use accordingly.

Factors to Consider When Deciding When to Use a Dehumidifier

When deciding when to use a dehumidifier, it's essential to consider several factors that can influence your home's humidity levels and your comfort:

  1. Indoor Humidity Levels: The first factor to consider is the current humidity level in your home. You can measure this using a device known as a hygrometer. In general, indoor humidity levels should be between 30% and 50%. If your home's humidity consistently exceeds 50%, it may create an environment conducive to mold growth and increased allergens, making a dehumidifier necessary.

  2. Seasonal Climate: The time of year and local climate significantly affect indoor humidity. Using a dehumidifier during summer may benefit areas with hot, humid summers. Conversely, in regions with cold, dry winters, using a dehumidifier may make the indoor air uncomfortably dry unless the home's humidity levels are unusually high.

  3. Home Construction and Insulation: Homes that are not well-insulated or ventilated may struggle with maintaining optimal indoor humidity levels. In such cases, a dehumidifier may be beneficial in both summer and winter. If your home is older, not well-sealed, or you've noticed issues such as condensation on the inside of your windows, a dehumidifier could help control excess moisture.

  4. Personal Comfort: Individual preferences can also influence when to use a dehumidifier. Some people may feel more comfortable in a slightly drier or humid environment. If your comfort levels vary significantly from the average humidity levels, a dehumidifier can help you create a more comfortable living environment.

  5. Health Considerations: Maintaining an appropriate humidity level can be critical if someone in your home has allergies or respiratory issues. High humidity can encourage the growth of mold and dust mites, which can trigger allergies and asthma.

Considering these factors, you can decide when to use a dehumidifier in your home.


When to use a dehumidifier in your home depends on various factors, including your local climate, indoor humidity levels, and personal preferences. In general, using a dehumidifier is more common during the hot and humid summer, but it may be necessary during winter if your home experiences high humidity. Regularly monitoring your home's humidity and adjusting your dehumidifier use accordingly can ensure a comfortable and healthy living environment throughout the year.