What Does a Dehumidifier Do? Types, Sizes, and More

Don’t sweat the excess humidity in your home—get a dehumidifier

Dehumidifier in stylish hallway
Photo: Meaco / iStock / Getty Images Plus / Getty Images
Dehumidifier in stylish hallway
Photo: Meaco / iStock / Getty Images Plus / Getty Images
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Your home’s humidity is a delicate balance. If you’re wondering what a dehumidifier does, we’ve got you covered.

While you want a decent level of moisture in the air to keep humans, animals, and plants happy, high humidity levels can cause inadequate airflow, poor ventilation, mold growth, warping and possible compromise of your home’s structural integrity, and worsened health conditions, such as allergies and asthma. Fortunately, dehumidifiers can mitigate excess humidity and maintain an ideal, consistent humidity level. This guide will review functions, types of dehumidifiers, costs, and when to hire a dehumidifier professional.

What Is a Dehumidifier?

Whole-house dehumidifier and how they work illustrated

A dehumidifier is an appliance designed to reduce the humidity in the air and maintain ideal indoor humidity levels in a home. It works by drawing in moist air, removing excess moisture, and then releasing drier air back into the environment. Dehumidifiers are commonly used to prevent mold growth, reduce allergens, and improve overall air quality in homes and other buildings.

Types of Dehumidifiers

There are several types of dehumidifiers, each suited for different needs:

  • Refrigeration Dehumidifiers: These are the most common type and work by cooling a metal plate to condense moisture from the air, which is collected in a tank. However, its performance suffers in cooler temperatures due to ice formation, making it less suitable for colder environments.

  • Desiccant Dehumidifiers: These units use a water-absorbing desiccant material to extract moisture from the air. They can operate at lower temperatures than refrigerant dehumidifiers and are smaller and lighter, but they consume a lot of power and are less reliable.

  • Whole-House Dehumidifiers: These dehumidifiers can be added to a furnace, providing consistent humidity control throughout the entire house. They are cost-effective and quiet, pushing fresh air from the loft space into the home and expelling damp air.

How Much Water Does a Dehumidifier Remove?

Woman changing water container in air dryer
Photo: Creative Cat Studio / Adobe Stock

Most dehumidifiers remove 30 to 70 pints of water per day. However, whole-house dehumidifiers can remove about 100 pints of water per day. The amount of water a dehumidifier removes depends on three main factors: the unit's power, the room temperature, and the relative humidity of the air. Once the relative humidity reaches your desired level, the dehumidifier will operate intermittently to maintain it, resulting in even less water collected in the bucket.

How Much Do Dehumidifiers Cost? 

The cost of installing a whole-house dehumidifier ranges from $1,300 to $2,800, depending on the type and capacity. As for other types of dehumidifiers, they can be anywhere from $150 to $3,000 or more, depending on the size, model, and brand. Small, portable models are available at the lower end of that price range, while larger, more industrial models are more expensive.

Signs You Need a Dehumidifier

The ideal humidity level for a home is around 50% but can range from 30% to 50%. A humidity level higher than 60% means you should consider installing a dehumidifier. There are several different ways to measure your home’s humidity, but the easiest method is using a hygrometer.

Aside from looking at the numbers, there are other signs that indicate your home’s humidity level is too high:

  • Musty, mildewy, or moldy odor 

  • Condensation on windows, mirrors, pipes, toilet bases, or any cool surface 

  • Water stains and crumbly areas on the ceiling

  • Peeling paint on walls and ceilings, especially in bathrooms lacking proper ventilation

  • Dampness or discoloration on furniture and other surfaces 

How to Choose the Right Size of Dehumidifier  

If you’re wondering, “What size dehumidifier do I need?” the answer depends on the square footage of the space and the level of humidity. For example, a small dehumidifier might work for a bathroom or closet, while a larger unit is necessary for basements or entire homes. Check the dehumidifier's capacity, which is typically measured in pints per day, to ensure it meets the demands of the space in question.

Dehumidifier SizeCapacity
Small capacity30–35 pints
Medium capacity35–50 pints
Large capacity50–60 pints

Who to Hire to Install a Whole-House Dehumidifier

If you’re interested in a whole-house dehumidifier, a local humidifier contractor is the ideal professional for the job. By hiring the right pro to install a whole-house dehumidifier, you can ensure the unit is properly connected to your furnace and functions efficiently. Professional installation also ensures that your warranty remains valid and the installation is up to code.

Can You DIY a Whole-House Dehumidifier Installation? 

Installing a whole-house dehumidifier requires professional expertise to ensure proper functionality and compliance with local codes. However, you can take several steps to reduce your home's humidity, such as using exhaust fans while cooking, limiting indoor plants, venting your dryer outside, and ensuring your HVAC system is in good working condition. 

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