Dehumidifier Size Chart: What size dehumidifier do you need?

Dehumidifier Size Chart

Are you looking for dehumidifier size chart? You come the right place here, below are general chart of dehumidifier size from 10 pint to 44 pint based on room size from 500 sq.ft. to 2500 sq.ft.

Are you looking for what size dehumidifier do you need?
Knowing the right dehumidifier size is the most important thing to get rid of the moist and sticky atmosphere. If you end up buying a dehumidifier that is too big or too small, you will either face a high electricity bill or a humid home. Different situations require different sizes of dehumidifiers. Picking a dehumidifier of the correct size is not the easiest task in the world but you don’t have to worry because we will help you to choose the best dehumidifier according to your needs. Our experts have prepared dehumidifier size charts for every situation. So, continue reading this ultimate guide that contains charts and instructions on how to size your dehumidifier.

Basic Definitions

It is important to understand the terms that are used in this guide for better understanding. So, let’s discuss some basic definitions.

  1. Pint: Dehumidifiers are sized by the pint and a pint is equal to 1/8 of a gallon. The amount of moisture a unit can remove in 24 hours is known as pints per day (PPD).
  2. BTU: BTU stands for British Thermal Unit and is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
  3. Slight Damp: A space that has a humidity level between 50-60% is known as slightly damp. The air in slightly damp spaces feels slightly heavy.
  4. Moderately Damp:  Moderately damp spaces occasionally have a clammy or musty smell. This happens when your place has a humidity level between 60-70%. Generally, this is not a year-round occurrence but occurs more frequently during humid weather.
  5. Very Damp:  When the humidity level is between 70-80%, it is categorized as very damp. In this case, you might notice wet spots on walls or floors. A musty odor is also present in most cases.
  6. Wet: This is the worst case. You might begin to see seepage on walls and floors and mold may also become apparent. Rooms will also feel damp and smell humid at all times. This happens when the humidity level is between 80-100%.

Dehumidifier Size Chart

The first thing that you need to do to calculate the required size of your dehumidifier is to measure the area or square footage of the place and the humidity level. Multiply the length by the width to find the area of the place. You can use a hygrometer to measure the humidity levels.  After that, you can use the chart given below to choose the right dehumidifier for your space.

ConditionsDehumidifier size chart
300 sq. ft.500 sq. ft.800 sq. ft.1200 sq. ft.
Slight Damp20 pints25-30 pints30-40 pints50 pints
Moderately Damp20 pints25-30 pints30-40 pints50 pints
Very Damp25 pints30 pints45 pints55 pints
Wet25-30 pints30-40 pints45-50 pints60 pints

Let us take an example to understand how you can choose the best dehumidifier with the help of the above chart. Suppose you have an 800 sq. ft. house that is very damp. It means that it has a humidity level between 70 to 80%. In this situation, a dehumidifier with a capacity of 45 pints is the best option for you. It will not lead to the waste of electricity and it will also solve the problem of moisture efficiently.

Factors to consider while choosing the right dehumidifier size

Even though buying a dehumidifier is the best option to get rid of the humidity, there are some factors other than the size. You should consider these factors while choosing a dehumidifier. These factors are important to consider because they can affect the performance of the device.

Relative humidity rates(RH):  You must keep relative humidity rates in your mind while choosing a dehumidifier. A place with a high humidity rate requires a dehumidifier of high capacity. If you ignore this factor, you will only increase your electricity bill without seeing desired results.

Square footage: The same logic applies to this factor. If you need a dehumidifier for a large place, you need a dehumidifier with high capacity. Use the chart above to find out how much capacity is required for a particular square footage.

Average temperature: Humidity and temperature are very closely related. Many people face the humidity problem in summer when the temperature is high. The dehumidifier will work efficiently if your place has a high average temperature. But as the temperature decreases, the dehumidifier needs to work harder. A desiccant dehumidifier is advised by the experts for a place that has a temperature of less than 10°C, If you have this need, this article is worth reading Best Dehumidifier for Cold Weather.

Dehumidifier costs: Before you rush to spend a lot of money on dehumidifiers, it is important to do thorough research. It would be best if you did not think that expensive is better. You will be able to find many good quality dehumidifiers at a range of prices and you should choose one that suits your needs and fits your budget.

 Air-conditioner: An air-conditioner’s primary function is to reduce the temperature and dehumidification is a side function. However, an air conditioner does not work well when the humidity level is high, this will make the air conditioner struggle to reduce the temperature. So, running a combo of dehumidifiers and AC is very efficient.

Pets and dehumidifiers: Dehumidifiers are safe for pets. In fact, there are various benefits of installing a dehumidifier if you have a pet. It keeps the pets healthy and reduces the risk of mold and allergies. Sometimes having a pet can create a smell in your house, a dehumidifier removes that odor, and your house smells fresh.

Crowded situations: A crowded place means more humidity, so it is best to get a dehumidifier that is energy efficient and powerful enough to handle the humidity of a crowded place. If you are looking for a dehumidifier for a crowded place, add additional 5-pints to meet the need.

Climate: It is best to choose a dehumidifier of high capacity if you are installing the device in a humid climate. Add 10 pints to the dehumidifier for a situation like this. You should also consider some other factors like surrounding water while choosing a dehumidifier. One more thing you should remember is that if you live in a cold region, a refrigerant dehumidifier will not work well well. So, you should use a desiccant dehumidifier if the temperature goes below 10°C (50 °F).

AHAM Dehumidifier Size Chart

Choosing the right dehumidifier is not an easy task. But the AHAM dehumidifier size chart makes it easy for homeowners to identify their situation. The Association of Home Appliance Manufacturers has issued guidelines on dehumidifier capacity for various relative humidity and area sizes. One thing you should be aware of before using the AHAM dehumidifier size chart is that the Department of Energy (DOE) has adopted two testing standards for modern dehumidifiers. The first standard is from 2012 and the new standard was adopted in 2019. So what is the difference between the two, why are there two standards, and how should you use this chart?

A dehumidifier that used to have a capacity of 70 pints has a capacity of 50 pints according to the new standard. This happened because the old standard used to consider Energy Factor while the new standard considers Integrated Energy Factor while measuring energy efficiency. Taking the Integrated Energy Factor into account while calculating the capacity of a dehumidifier give more accurate results.

The new testing method also tests the devices at a lower temperature of 65 °F and 60 % humidity while the 2012 standard tests dehumidifiers at an ambient temperature of 80°F and 60 % humidity.

Here is the AHAM dehumidifier size chart that includes both the old and new standards that will help you in both situations.

ConditionsAHAM Dehumidifier Size Chart
(Old standard)
300 sq. ft.500 sq. ft.800 sq. ft.1200 sq. ft.
Slight Damp30 pint45 pints60 pints70 pints
Moderately Damp30 pint45 pints60 pints70 pints
Very Damp40 pint50 pints65 pints80 pints
Wet45 pint60 pints70 pints90 pints
ConditionsAHAM Dehumidifier Size Chart
(New standard)
300 sq. ft.500 sq. ft.800 sq. ft.1200 sq. ft.
Slight Damp20 pints30 pints40 pints50 pints
Moderately Damp20 pints30 pints40 pints50 pints
Very Damp25 pints30 pints45 pints55 pints
Wet30 pints40 pints50 pints60 pints

Example for AHAM dehumidifier size chart

Suppose you need a dehumidifier for your 1200 sq. ft. house. You measured the humidity with the help of a hygrometer and it was 65%. As we discussed above in the article, 65% means moderately damp conditions. Once you know the area of the place and the relative humidity, you can easily use the AHAM dehumidifier chart to find the most suitable dehumidifier for your situation. In this case, you will see that you need a 70-pint dehumidifier according to the old standard or a 50-pint dehumidifier according to the new standard.

Dehumidifier Size chart for the whole house and basement

The AHAM dehumidifier size chart is very helpful in choosing a dehumidifier for your garage or house or places that are less than 1200 sq. ft. But what about the places that are larger than 1200 sq.ft.? For larger areas like crawl spaces, basements, or whole houses that are large in size, you should decide the size of the dehumidifier on the basis of your building’s sealing. To put it in simpler words, you should figure out if your building is loosely, moderately, or tightly sealed.

A dehumidifier of a specific capacity will be able to cover more area if a place is tightly sealed in comparison to a loosely or moderately sealed place. This is because a tightly sealed house or basement does not allow more humidity to enter the area. On the other hand, moisture or humidity continuously enters a loosely sealed place which puts more load on the dehumidifier. We have prepared a chart for you to help in choosing the correct dehumidifier size based on the size of the place.

ConditionsDehumidifier sizing chart
for the whole house and basement
70-80 pint85-100 pint100-155 pint
Loosely SealedUp to 1800 sq. ft.Up to 2200 sq. ft.Up to 3600 sq. ft.
Moderately SealedUp to 2200 sq. ft.Up to 2600 sq. ft.Up to 4000 sq. ft.
Tightly SealedUp to 2600 sq. ft.Up to 3000 sq. ft.Up to 4400 sq. ft.

To read the chart, you must be aware of what would be considered a loosely, moderately, or tightly sealed place.

Loosely Sealed: Most of the older houses having minimal air sealing are considered loosely sealed houses. These houses have foundations with many cracks and imperfections. Spaces with plastic vapor barriers on the floor are also considered as loosely sealed.

Moderately Sealed: New or remodeled houses with some air-sealing capacity are called moderately sealed houses. These houses have fewer cracks and imperfections in the foundation compared to the loosely sealed houses.

Tightly Sealed: These are the new houses that pass a recognized energy building standard. Tightly sealed houses have a 3 ACH50 or less confirmed air leakage. Tightly sealed spaces are fully encapsulated.

Let’s take a look at examples of how to use the chart given above to choose the perfect dehumidifier.

Example 1. Moderately sealed 2500 sq. ft. Basement

Suppose you have a basement of 2500 sq. ft. and it is moderately sealed. The basement has some air-sealing capacity. If you look at the moderately sealed row in the chart given above, you will realize that you need to choose a dehumidifier that is suitable for up to 2600 sq. ft. This means that you need a dehumidifier with a capacity in the range of 85-100 pints. Don’t forget to consider other factors also while choosing a dehumidifier. For example, if you live in a very humid climate, you are advised to add 10 pints to the capacity of your dehumidifier.

Dehumidifier Size chart for square footage

The chart in this article’s previous section helps you choose the right dehumidifier for large spaces like whole houses and basements. But what if you want to choose a dehumidifier for a small house or a room? You don’t have to worry, we have also prepared a Dehumidifier Size chart for square footage. With the help of this chart, you will be able to decide the size of the dehumidifier of your requirement.

Dehumidifier size chart for square footage
Room SizeDehumidifier Size
400 sq ft25 pints
500 sq ft30 pints
600 sq ft35 pints
800 sq ft45 pints
900 sq ft50 pints
1,000 sq ft55 pints
1,200 sq ft60 pints
1,500 sq ft65 pints
2,000 sq ft70 pints
2,500 sq ft80 pints

The first step you need to follow to read this chart it to find out the square footage of your place. It is very easy to do that. Measure the length and width of the floor by using a measuring tape. Multiply these two dimensions to get the square footage. For example, if you are working with a place that has a length of 20 feet and breadth is also 20 feet, then the area is 400 sq. ft. According to the chart, you need a dehumidifier with a capacity of 25 pints for a 400 sq. ft. room.

Dehumidifier Size chart for crawl space

Finding the perfect dehumidifier for your crawl space can prove to be very tricky because of different humidity conditions and varying sizes of the place. It is very difficult to give a general recommendation for a crawl space dehumidifier because some crawl spaces can be much larger than others. The sealing conditions must also be considered while choosing a dehumidifier for a crawl space. Let’s understand how to calculate the dehumidifier size for your crawl space step by step.

Step 1. Calculate the volume of your crawl space

To get more accurate and better results, we recommend using the volume of your crawl space instead of square footage. Measuring the volume is as simple as measuring the square footage. Carefully measure the three dimensions of your crawl space (length, width, and height). To get the volume, multiply your readings.

Step 2. Classify the condition of your crawl space

A crawl space can be divided into three different categories based on the extent of sealing. A crawl space could be loosely sealed, tightly sealed, or completely unsealed. Figure out if your crawl space is tightly sealed or loosely sealed based on the definitions given above, Dehumidification does not work for an unsealed dehumidifier as it is continuously subjected to humidity through the air and periodic flooding.

Step 3. Determine how much capacity or pints are required

Use the chart given below to find out what should be the capacity of dehumidifiers you need. For example, if you have a crawl space of 14,000 cubic feet and the crawl space is tightly sealed, according to the chart you need to install a dehumidifier with a capacity of 150 pints.

Dehumidifier Size chart for crawl space
Size of Place(cubic feet)Tightly sealed (Pint)Loosely sealed (Pint)
7,500–15,000150600 300
15,000–22,500450    2253600  450
22,500–30,0001800  30028800  600
30,000–37,5009000   375288000   750
37,500–45,00054000  4503456000   900
45,000–52,500378000  52548384000   1050

Dehumidifier Size chart for grow room

Many people often do not think about the moisture buildup from the plants while setting up a grow room. It is a common mistake, and it can prove to be costly because plants transpire 97% of the water they receive. A dehumidifier is a must for anyone who has more than 5,000 square feet of grow space or more than 50 lights. Getting the right size dehumidifier is important for the health of your garden. If you choose a smaller dehumidifier, you may encounter serious problems such as powdery mildew, pests, and mold.

Factors to choose the right dehumidifier size for your grow room:

There are some factors that you should consider while choosing a dehumidifier for your grow space.

  1. Number of plants: The best method to calculate how much moisture buildup will occur in the grow room is to count the number of plants. Then, determine how much water these plants will receive. For example, 40 plants that receive 1 gallon of water per plant will create almost 40 gallons of moisture.
  • Growing environment: Different types of plants require different environments and temperatures to grow. If the climate is generally humid and you are using ventilation, then factor in an additional 10 pints. If many people spend time in the grow room, factor in an additional 5 pints.
  • Size of grow room: The size of the grow room is one of the most important factors to consider when choosing the size of your grow room’s dehumidifier. A large grow room usually has a lot of plants, hence a powerful dehumidifier is required for such a grow space. You can use the chart given below to determine the ideal grow room size per plant. This will help to easily calculate the square footage and it can also prevent overcrowding inside the grow room.
Growing MethodAvg. Square Footage Per Plant
Sea of Green (SOG)1
SCReen of Green (SCROG)4
Super cropping2

After considering the important factors, calculating the size of the dehumidifier becomes very easy with the help of the dehumidifier size chart for grow room. All you need to do is identify the growing method and the number of plants you have in your grow room.  For example, if you use the super cropping method and you have 500 plants in your grow room, you can easily find out that your grow room needs a dehumidifier of 500 pints.

Growing MethodDehumidifier Size chart for grow room
300 plants500 plants1000 plants1500 plants
Sea of Green20 pints33 pints67 pints100 pints
SCReen of Green80 pints133 pints267 pints400 pints
Topping or Fimming30 pints50 pints100 pints150 pints
Super cropping40 pints67 pints133 pints200 pints

You can also use a simple formula to calculate the required size of your dehumidifier. Firstly, you need to calculate how many plants you have and how much water you are giving to your plants daily.

Dehumidifier Size (pints) = Number of plants × gallons per plant per day × 8

If you are using hydro systems, you need to consider the water capacity of your system. In this case, you will have to divide the equation by 7. This is because you will be changing out your reservoir every 7-10 days. According to our experts, the equation given below gives better results while calculating dehumidifier size for hydro systems.

Dehumidifier Size (pints) = (Gallons of Hydro System × 8) / 7 (Days per week)

A dehumidifier is very helpful in decreasing humidity from the air. But it works well only if you have chosen the appropriate size. If the size is too small or too big, it will not have good results. To choose the perfect dehumidifier, you can follow the instructions mentioned in this guide and use easy-to-read charts prepared by our experts. These dehumidifier size charts will help you find the most suitable dehumidifier for your house, basement, crawl space, grow room, etc.


I am Johnson, welcome here. I love RV travel, and RV is more than simply a mode of travel for me, it is a way of life. But terrible humidity and mold destroy my freedom and happiness, so I started to share my own experiences and sources of dehumidifiers to generate even more value. You can find out more about my story here or follow me on Youtube if you wish. If the humidity is also trapped around you, the articles here will have some tips and suggestions and reviews of dehumidifier, hoping to help you and more people.

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