The ideal room humidity for comfort and health is between 30% and 50%. If the relative humidity in your air is consistently running higher than that, a dehumidifier is what you need. Here is some information to help you make the right choice of a humidifier for your room, apartment, basement or home.
This Dehumidifier Sizing Guide includes three separate Tables showing the right size dehumidifier based on
- Room square feet
- Room dimensions
- Dehumidifier sizes chart showing the amount of moisture dehumidifiers of different sizes remove per day
The Dehumidifier Tables are followed by more useful information that will help you select the right option for your purpose.
Dehumidifier Size Factors
When shopping for a dehumidifier, there are three main things you need to know to choose the right size and model of dehumidifier: The size of the area to be dehumidified, how humid the area is, and special features you want to have on your unit.
Knowing these three things will help you determine the dehumidifier you need for your purpose. So, let’s explore them before looking at the charts.
Determining Dehumidifier Size by the Square Footage of a Space
What is the square footage of the room or base? Or the apartment size?
In rectangular spaces, measure length x width to get square feet. In an apartment, you might already know the total square feet – or the apartment manager should know.
There are a few examples below to show how this chart is used.
Dehumidifier for 400 – 2,500 sq ft
|Room Size (sq ft)||Dehumidifier Size (Pints)|
|400 sq ft||25 pints|
|500 sq ft||30 pints|
|600 sq ft||35 pints|
|800 sq ft||45 pints|
|900 sq ft||50 pints|
|1,000 sq ft||55 pints|
|1,200 sq ft||60 pints|
|1,500 sq ft||65 pints|
|2,000 sq ft||70 pints|
|2,500 sq ft||80 pints|
What size dehumidifier for 1000 sq ft is needed?
To answer that question, simply find 1,000 square feet in the left column, and the right column shows that a dehumidifier with a 55 pints per day capacity will effectively dehumidify that area.
What’s the right dehumidifier for 500 sq ft?
Again, locate the room size, or 500 sq ft, in the left column. Scan to the right to see that you’ll need a dehumidifier that removes at least 30 pints of moisture per day.
Determining Dehumidifier Size by Room Dimensions
This chart is often used to determine the right dehumidifier size for a basement bedroom or other damp place, but it works for any room or zone that needs the air dried out a little.
|Room||Room Size (sq ft)||Dehumidifier Size (Pints)|
|10 x 10 room||100 sq ft||10 pints|
|12 x 12 room||144 sq ft||10 pints|
|12 x 16 room||192 sq ft||15 pints|
|13 x 13 room||169 sq ft||15 pints|
|15 x 15 room||225 sq ft||20 pints|
|15 x 25 room||375 sq ft||25 pints|
|20 x 20 room||400 sq ft||25 pints|
|20 x 40 room||800 sq ft||45 pints|
|24 x 24 room||576 sq ft||35 pints|
|24 x 30 room||720 sq ft||45 pints|
|27 x 37 room||1,000 sq ft||55 pints|
|40 x 48 room||1,920 sq ft||70 pints|
If you have measured a room and found it to be 12 x 12 feet, for example, you can tell that a dehumidifier that can remove 10 pints of water per day would be ideal. This is seen in the fact that the row above it shows that a dehumidifier that size can also handle a room that is a little larger.
My room dimensions aren’t on the chart!
If your measurements don’t match any of those listed in the chart, you can easily find the one that is closest to your numbers. For example:
What’s the right dehumidifier for 500 sq ft?
If your room measures 20 x 25 feet, which is 500 square feet. This chart doesn’t show what dehumidifier for 500 sq ft is needed, so choose the next larger room size, which is 576 square feet. Now you know that a humidifier with a capacity of 35 pints will adequately work for your situation.
Determining What Size Room a Dehumidifier Can Cover
Do you have a dehumidifier and wonder if it will be big enough to dry the air in your space?
This dehumidifier sizes chart is here to help. A few examples follow to show how to use the table – though it’s quite simple.
Dehumidifier room size
|Dehumidifier Capacity (Pints)||Room Size (sq ft)|
|20 pints||300 sq ft|
|22 pints||400 sq ft|
|35 pints||600 sq ft|
|40 pints||700 sq ft|
|50 pints||900 sq ft|
|70 pints||2000 sq ft|
What’s the 35 pint dehumidifier room size?
By this chart, you can quickly see that the 35 pint dehumidifier room size is 600 square feet.
How many square feet does a 70 pint dehumidifier cover?
Simply find that number in the left column and you will see that it will dehumidify a room up to 2,000 square feet.
How Humid is My Living Space?
You need a dehumidifier because your space is too humid – but how humid is it?
A very damp room might need a bigger dehumidifier than listed. And a “just a little damp” room might need one that is slightly smaller.
Here are three levels of a room or living space that is too humid and how to think about your dehumidifier size accordingly:
- Somewhat Damp – a “moist” feel, light moisture on windows, and perhaps a musty smell – add 2-3 pints to the capacities listed in the charts above for each 500 square feet of space.
- Wet – Water beading on windows, ceiling or walls; an obviously “wet” feel or you see traces of mold and mildew forming – add 4-5 pints to the capacities listed in the charts above for each 500 square feet of space.
- Very Wet – Water standing on the basement floor, or on windowsills on other levels – add 6-7 pints to the capacities listed in the sizes chart above for each 500 square feet of space.
Other humidity factors to consider when determining the size of your dehumidifier are:
- If you live in a very humid climate like the southeast and southern US, add 10 pints to the dehumidifier size. For example, if you want to dry 800 square feet, the table suggests a 45 pint unit. Go with a 55 pint dehumidifier to be sure you remove enough humidity to make the space comfortable.
- If there are more than 5 people living in the house or apartment, add 5 pints to the dehumidifier size.
- If the space has many windows and exterior doors, add 5 pints to the dehumidifier size.
- If there is a washer and dryer nearby, add 5 pints to the dehumidifier size.
What Features Do I Need or Want?
After you have determined how big a dehumidifier you need for your room or apartment size, there are many features that dehumidifiers may have that can affect your choice:
Drain Pump – portable dehumidifiers have a holding tank to collect water removed from the air. But if you need to dehumidify a very large and/or wet space, you might have to empty the tank several times a day.
Easy Drain Line – If you are using it in a basement, you may attach a drain hose to the unit and run it to a floor drain for continual draining. But if it is in a large room with no floor drains, some models have a pump and long drain line that can be routed to a sink or even out a window to get rid of the water.
Humidistat – A humidistat is an electronic sensor that will measure the humidity in the room and shut off the dehumidifier when it reaches the number you have it set to. Think of a thermostat but for moisture.
Auto-Defrost – If you are operating your dehumidifier in a very cool space, it may “freeze up”, meaning that frost will form on the coils that normally remove moisture from the air. The auto-defrost feature will enable the unit to temporarily stop dehumidifying while it melts the frost. Then it will continue to function normally.
Casters on the Cabinet – in a large room or basement, having casters that allow you to easily roll the unit around can be very helpful. This is especially true if you need to empty the tank frequently.
Can a dehumidifier be too big?
Unlike a humidifier, you don’t need to worry about purchasing a unit that is too large for your space. Most dehumidifiers have the ability to be set to a certain level of humidity you want to attain. If it doesn’t have a humidistat so you can set it at a specific degree of humidity, it will at least have a way to set the range of humidity you want, such as Low/Medium/High.
Is a 50 pint dehumidifier enough for the basement?
The Dehumidifier Room Size Table above shows that a 50 pint unit can remove sufficient moisture from 900 square feet. If your basement is smaller or larger, see the Table for sizing your dehumidifier to do the job.
What size dehumidifier do I need for a 3 bedroom house?
It depends on square footage. Most 3 bedroom homes are 1,500 to 2,000 square feet. According to the first Table above, you’ll need a dehumidifier that can remove 65 to 70 pints per day.
What type of dehumidifier do I need?
First, make sure it is the right size by using the charts above. Then read the What Features Do I Need for information that will assist you in choosing the right type of dehumidifier for your budget and convenience needs.