What Size Dehumidifier Do I Need

How big of a dehumidifier do I need?If you are faced with hot and humid weather or are dealing with a damp room or basement you need to be prepared to address the humidity and the problems it can bring. Dehumidifiers remove excess moisture from your home and provide a lot of benefits to your health, home, and belongings.

Choosing a model that is the right capacity (size) is paramount when buying a dehumidifier. They come in a wide variety of sizes, which can make selecting the right one for your living space confusing. So let’s discuss the basics of dehumidifier size so you can choose the best dehumidifier for your home.

Do I Need a dehumidifier?

When contemplating buying one for the first time most people will first ask themselves; do I really need a dehumidifier? For most of us, the answer is usually yes.

High humidity can damage furniture, clothing, electronics, and wallpaper. It can make many areas of your home unbearable and/or unhealthy. In rooms, such as laundry rooms and basements where higher levels of dampness are common due to natural conditions, a dehumidifier can help solve your problems. Plus, it will reduce those musty odors. You can learn about all the benefits of dehumidifiers here.

Even if you own a home air conditioner, there might be enough moisture in the air of your home to still make having a dehumidifier be a necessity during the summer months. This happens when the air conditioner gets the home to the desired temperature and shuts off (like it is supposed to do) despite the humidity levels still being higher than you would like. However, the need for a dehumidifier doesn’t necessarily end once fall comes. Many homes have problems with excess moisture year-round.

Thankfully, a dehumidifier can help us to maintain the recommended relative humidity level in our homes regardless of which season we are in. The EPA states that relative humidity (RH) should be kept below 60 percent — with levels between 30 percent and 50 percent being ideal.

Main Types of Dehumidifiers

There are two main types of dehumidifiers namely: refrigeration and desiccant dehumidifiers. Each type has different strengths and weaknesses. So understanding the differences can help you purchase the correct model for your situation.

Desiccant Dehumidifiers

Desiccant dehumidifiers work well in spaces that require consistent dehumidification, including laundry rooms, basements, or garages. One advantage of desiccant dehumidifiers is that they can work at low air temperatures (below 65°F ), which can cause refrigeration style dehumidifiers to freeze up and stop working.

They work by passing the air through the rotor that contains materials (such as silica gel) that absorb and hold water vapor. These materials usually absorb water from the air, after which the air is then pushed back out through vents into the room. Eventually, the desiccant material is heated, which vaporizes the water that it is then ducted out of the room.

In addition to working well in cooler temperatures, there are a couple of other positives about desiccant dehumidifiers. First, unlike the refrigerant types, desiccant dehumidifiers don’t have a compressor or use any refrigerants, which makes them easy to maintain. Second, because they don’t have a compressor desiccant dehumidifiers have lower noise levels and usually run quieter than their refrigeration style counterparts.

Refrigeration Dehumidifiers

Refrigeration humidifiers are by far the best at eliminating and removing excess moisture from the air compared to desiccant dehumidifiers, especially at high moisture and higher temperatures. This unit comes with refrigerated coils that help to drive the moisture out simply by pulling the damp, warm air from within the room and passing it over these cold evaporator coils that cool the surrounding air below its dew point temperature. In turn, the gaseous water in the air undergoes condensation. Then, the condensed water is automatically captured by the machine and directed into the storage unit. After some time, the water is ejected from a dehumidifier machine through the floor drain, and the dried air is released into your room or the facility’s environment.

Refrigeration style dehumidifiers are more energy-efficient and consume less energy per hour and are thus generally cheaper to run and own.

The vast majority of people are buying dehumidifiers for use in their homes and don’t need to worry about having to operate the dehumidifier in colder temperatures because of this and the fact that they are more energy-efficient, the most common type of dehumidifiers people buy are the refrigeration style. 

How to Calculate Your Needs?

Different room sizes and conditions require different dehumidifier ratings. Various factors will determine the best dehumidifier capacity for your room or house. Therefore, when selecting your model, these are the two main factors to consider:

The Size of Your Room or House You Wish to Dehumidify (Square Footage)

First, think about the size of the house you want to dehumidify. Remember to measure your room in square meters. Noticeably, that is the unit given or quoted by the manufacturer. Also, you need to decide on the space your tool will cover. To this end, you must calculate the square footage.

Consider Dampness In The Area You Wish to Dehumidify

Choosing a model based on the size of your room as well as its capacity alone isn’t enough, though. To come out with the best solution, you need to consider the conditions of your room. So you need to ask yourself this question- How damp is my space? Stick with the capacity that matches your space. If your space has lower levels of humidity, choose a smaller-capacity unit. If you want to tackle an extremely wet space, then go with a larger capacity unit.

So let’s talk about different levels of humidity and how you might be able to identify them without the use of a humidistat. For the purposes of our discussion let’s break it down into four categories

  • Moderately Damp (RH level between 50 and 60 percent) – There is an occasional musty smell and feels damp.
  • Extremely Damp (RH level between 60 and 70 percent) – It often smells musty and will often feel damp.
  • Wet (RH levels of between 70 and 85 percent) – Area feels wet and smells musty with damp spots on walls and/or floors.
  • Extremely Wet (RH level that’s greater than 85%) – Area feels wet and smells musty with water seepage appearing on the walls and/or floors. You may also notice mold growing.

So What Size Dehumidifier Do I Need?

So once you have decided what type of dehumidifier you want to have you need to think about the size or capacity, that will be best for the area you will be putting it into. Units are usually categorized by the number of pints of water they can collect in a 24 hour period. They come in four main categories.

Which category you should be considering is largely determined by the size of the space you are trying to dehumidify and the level of moisture in the air. Let’s take a look at the different categories.

Small Dehumidifiers

Maybe you only have slight excess moisture problems in just one small area of your house. If that is the case, you might want to look at getting a small (or mini) dehumidifier. There are units that are designed to be in areas that are 200 square feet or less and spaces that are between 200 and 300 square feet.

Because of their small size, these models are great for small spaces such as bedrooms, bathrooms or enclosed kitchens. However, some of these units might only hold around a full pint of water and only remove 1/2 pint per day. Due to the limited amount of moisture they can remove from the air each day you want to remember that they aren’t the solution for larger areas or spaces with very high humidity levels.

30 Pint Dehumidifiers

These models are suitable for areas between 500 and 3,000 square feet depending on the dampness. Each day, they collect about 30 pints of water and are appropriate to use in residential spaces including basements. Here is some more information on when to use 30 pint units:

  • 500-1500 square feet – Good for extremely wet spaces with RH up to levels that are greater than 85%
  • 2000 square feet – Good for extremely damp spaces with RH up to levels between 60 and 70 percent
  • 2500-3000 square feet – Good for moderately damp spaces with RH up to levels between 50 and 60 percent

50 Pint Dehumidifiers

50 pint dehumidifiers can handle middle-sized spaces that are extremely humid or large spaces that are a little less humid. These units are powerful enough to work well in areas that smell musty and damp all the time. Here is a little more guidance on when to buy a 50 pint dehumidifier:

  • 500-1000 square feet – A 50 pint humidifier is probably too big and unnecessary for this size of space.
  • 1500 square feet – Good for extremely wet spaces with RH up to levels that are greater than 85% (A 50 pint dehumidifier might be a little too much for a space this size if it has lower humidity levels )
  • 2000-2500 square feet – Good for extremely wet spaces with RH levels that are up to and greater than 85%
  • 3000 square feet – Good for wet spaces with RH up to levels up to the 70 and 85 percent range

70 Pint Dehumidifiers

If you need a dehumidifier for a large space and/or dealing with extreme humidity plaguing your home during hot and humid months, then a 70 pint dehumidifier could be your answer. These models can easily remove about 70 pints of water a day. They are superb for homes with very wet crawl spaces and basements. Here is some advice on the situations where you will want to consider a 70 pint dehumidifier:

  • 500-2000 square feet – A 70 pint humidifier is probably too big and unnecessary for this size of space.
  • 2500-3000 square feet – Good for extremely wet spaces with RH levels that are up to and greater than 85%

Other Things to Consider

As we just stated, the square footage of the space and the overall level of dampness are the two biggest things to consider when deciding the capacity of the dehumidifier you need. However, there are some other factors that might make you increase your calculations and decide to get a higher capacity model.

Number of People In the Home

As humans, we are constantly expelling water into our environment. Whether we are talking, breathing or sweating our bodies are releasing moisture that is being absorbed by the air around us. So it only makes sense that the larger the number of people who live in a home the need for a higher capacity dehumidifier increases. Some places suggest that you will need an additional 5 pints of capacity for every 4 people in your house.

There are some additional factors associated with the number of people[le in your home that might require you to think about a higher capacity dehumidifier.

Washer and Dryer

If your home has a laundry room, then it requires additional water-removing capacity. This is because water is constantly flowing and evaporating whenever you run your dryer or washer. If you have a larger family or just simply do a lot of laundry you might want to add more 5 pints to your overall calculation.

Windows and Doors

One way moisture can sneak into your house via open doors and windows.

If you live in a humid area and have a lot of people constantly coming and going or if you simply like to leave the windows and patio doors open to get fresh air in the house you might want to add another 5 pints of capacity to meet your home’s needs.


Your bathroom is a room that bacteria and mold loves. Simply flushing your toilet, running showers and washing your hands can increase the relative humidity of your bathroom.

If you like to take long showers or if there are a lot of people living in your home who are taking multiple showers per day you might want to add another 5 or 10 pints to your calculations. This is especially true if your bathroom isn’t very well ventilated.

Why Not Just Get The Largest Capacity Unit You Can Find?

Getting a 70 pint model might not be a bad idea, but it might not be the right thing for you to do either.


There are several reasons why you might not want to get a model that is bigger than you need. One reason is that you could spend a lot of extra money. Another reason is that a larger unit will usually make more noise than a smaller unit and depending on where you put it noise could be an issue for you. Finally, the bigger the capacity the larger the dehumidifier will be larger and weigh more (70 pint units can be about 50 pounds), which can be an issue if you plan on putting the dehumidifier in a small space or plan on moving it around to different areas of the house.


Getting a large capacity model can be a good choice for several reasons. First, you know that it will be able to meet your needs and get the humidity to a healthy level in your home. Second, because it will be able to get the moisture out of the air faster than smaller models it might be more energy-efficient than a slightly smaller unit that needs to run virtually non stop to get the job done. Lastly, a larger capacity unit might last longer than some of its smaller capacity counterparts since it won’t have to run as long to do the same job.


Selecting a model with the proper size (capacity) is arguably the most important part of buying a dehumidifier. If you take a few minutes to think about the size of your home and the level of moisture in the air you will be able to successfully find a dehumidifier that will be able to meet your needs for years to come. That being said, if you are having a hard time deciding, remember to error on the side of going with the larger capacity option if you are having a hard time.