What Size Dehumidifier Do I Need?

Dehumidifier Size

If you have been considering a dehumidifier for your home, choosing the right model all comes down to one important question. What size humidifier do I need? That’s the starting point in finding the perfect dehumidifier for your home, and there’s a good reason why capacity is critical with these types of machines.

Do you need a dehumidifier?

Before we talk about the different sizes of dehumidifiers available for residential use, it’s a good idea to make sure a dehumidifier is the right device for the issues you’re experiencing in your home. Simply put, these systems are designed to pull excess moisture from the air. Humidity in your home can cause a variety of problems, from paint peeling off of walls to mold and mildew.

If you have a humid home or a particular room that takes a hit in the summer, a good dehumidifier can certainly solve your problem. A dehumidifier doesn’t remove or clear up existing mold, however, so you still need to address any issues caused by the humidity.

Getting rid of mold present in a window AC unit is relatively simple, but having it removed from a damp basement can be an expensive endeavor. Having a high-quality dehumidifier in your home can stop that problem before it starts.

Whole House vs. Portable Dehumidifiers

When most consumers think dehumidifier, the first thing to come to mind are portable models that can sit in the corner of a room. Well, that’s only one type of dehumidifier, and compact models are only built to deal with rooms up to a certain size.

If you have a seasonal humidity issue, a portable system is your best bet. They are cheaper upfront but can cost more to operate and maintain over time. You’ll also need to account for the space it requires, noise, and getting rid of the moisture the machine collects. On the plus side, you can move it from room to room as needed, and they are simple to operate.

whole-house dehumidifier

As the name implies, a whole-house dehumidifier can handle moisture throughout an entire home – not just one room. While you still have to keep placement and size in mind, these machines hook into the existing ductwork in your home, so they don’t need to be placed in a living area. Unfortunately, they can be quite expensive and usually require professional installation. 

If you need to clear up the air in a room or space larger than 2,000 square feet, it may be time to consider a whole-house dehumidifier. They can cover large homes and treat the air before it enters our home. Now that you have an idea of the type of system you need, it’s time to talk about the size ranges available from dehumidifier manufacturers.

Dehumidifier Size Ranges

The specification to look for with dehumidifier sizes is capacity. This tells you how much moisture a system is capable of removing within a 24-hour period. You’ll often hear the term PPD as well, which stands for pints per day, the measurement used for measuring capacity in dehumidifiers. It’s important to remember that the capacity listed is just a “rough” number as a variety of factors can affect how well it performs in your home.

Testing Standards and Sizes

Any dehumidifier sold in the United States must meet certain criteria, and the Department of Energy or DEO deals with power consumption and efficiency. The DOE tests all dehumidifiers’ energy efficiency and pint capacity, which is where the sizes come into play. In the past, the market had 70, 50, and 30-pint dehumidifiers based on testing standards with an ambient temperature of 80°F and 60% humidity.

In 2019, those standards changed, and so did the sizes. Currently, DOE tests at 65°F and 60% humidity, so the new formats are 50, 30, and 20-pint dehumidifiers. In other words, you are likely to find both ranges for sale at multiple retailers until the previous models are eventually phased out. With that in mind, here is a chart that allows you to hone in on a size based on square footage.


Pre-2020 Capacity

New Capacity

400 sq. ft.

30 pint

20 pint

600 sq. ft.

40 pint

25 pint

800 sq. ft.

50 pint

30 pint

1000 sq. ft.

60 pint

35 - 40 pints

1200 sq. ft.

70 pint

45 – 50 pints

1500 sq. ft.

90 pint

55 - 60 pints

 (numbers from here)

Keep in mind, damper areas with a higher humidity level will require a more robust system. You can use a digital humidity meter to get a reading quickly, but can also diagnose the problem through sight and smell.

Do your walls sweat? That’s common in areas with high humidity and calls for a dehumidifier that works flawlessly if you want to keep mold and other issues at bay. If the room just smells a little musty the summer months, you don’t necessarily need a workhorse of a machine. If you have standing water, you have a more severe problem at hand and one you’ll want to address before buying a dehumidifier.


Q: Can I use a portable dehumidifier in smaller areas?

A: There are a number of small dehumidifiers for rooms under 400 square feet, but they aren’t ideal for areas with high humidity.

Q: What humidity level should I try to keep in my home?

A: Ideally, you’ll want a relative humidity level between 40 – 50% as high levels can create mold, but low levels will also cause problems in your home.

Q: Should I use a whole-house dehumidifier to clear up moisture in a crawl space?

A: If you have excess moisture in a crawlspace, they have systems designed for those spaces. We touched on some of the top models in our list of the best dehumidifiers for crawl spaces.

Q: Should I use a dehumidifier if I live in an area with a colder climate?

A: For areas that remain cold most of the year, a desiccant dehumidifier is an excellent choice, whereas you’ll want a refrigerant-based system in hot weather. 

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