Home AppliancesDehumidifier

How To Calculate Dehumidifier Size

Dehumidifier 11

Calculating the size of a dehumidifier for your home or office space is crucial for maintaining a comfortable and healthy indoor environment. A dehumidifier that is too small may not effectively control humidity, while a unit that is too large might consume more energy than necessary. But how do you determine the right size? This comprehensive guide will take you through the steps of calculating dehumidifier size, with examples and statistics to help you make an informed decision.


To calculate the size of a dehumidifier, measure the room’s dimensions to calculate the square footage, assess the room’s humidity level, and then refer to a sizing chart to determine the appropriate dehumidifier size. For example, a slightly damp 500 sq.ft. room would require a 25-pint dehumidifier, while a very damp 800 sq.ft. room would need a 50-pint dehumidifier. Remember to consider additional factors such as the presence of air conditioners or appliances that may affect humidity.

Understanding Dehumidifier Size

Firstly, it’s important to understand that the size of a dehumidifier is determined by its capacity to remove moisture from the air, measured in pints per day. This capacity depends on two factors: the size of the space that needs to be dehumidified and the conditions that exist in the space before dehumidification.

Step 1: Measure the Room’s Dimensions

The first step in calculating the size of dehumidifier you need is to measure the room’s dimensions. You can use a tape measure to determine the room’s length and width, and then multiply these measurements to find the square footage. For instance, if your room measures 12 feet by 12 feet, the square footage would be 144 square feet (12 x 12 = 144).

Step 2: Assess the Room’s Humidity Level

Next, assess the room’s humidity level. You can use a hygrometer for an accurate measurement, or you can estimate the humidity based on the room’s conditions. As a general rule, if the air in the room feels slightly heavy and there’s a musty odor in damp weather, the room has a humidity level of 60-70%.

Step 3: Choose the Right Dehumidifier Size

Now that you know the room’s square footage and humidity level, you can determine the right dehumidifier size. Here’s a chart to help you choose:

| Conditions in your Space | 300 sq.ft. | 500 sq.ft. | 800 sq.ft. | 1,200 sq.ft. | |————————–|————|————|————|————–| | Slightly Damp (50-60% Humidity) | 20 pint | 25 pint | 30 pint | 40 pint | | Moderately Damp (60-70% Humidity) | 25 pint | 30 pint | 40 pint | 50 pint | | Very Damp (70-80% Humidity) | 30 pint | 40 pint | 50 pint | 60 pint | | Wet (80-100% Humidity) | 35 pint | 45 pint | 60 pint | 70 pint |

Consider Additional Factors

Apart from room size and humidity level, other factors can influence the humidity of the room. For instance, the presence of air conditioners, heating systems, and appliances like a washer/dryer can affect the room’s moisture levels. Consider these factors when choosing a dehumidifier size.


Selecting the right dehumidifier size is not a one-size-fits-all process. It requires careful consideration of the room’s size, humidity levels, and other specific conditions. By following the steps outlined in this guide, you can effectively calculate the right dehumidifier size for your space, ensuring optimal performance and energy efficiency.

Frequently Asked Questions

What is a hygrometer and where can I purchase one?

A hygrometer is a device that measures the amount of humidity in the air. You can purchase a hygrometer at a home improvement store, an electronics store, or online.

How often should I run my dehumidifier?

The frequency of running your dehumidifier depends on the humidity level in your room. If the room is very damp or wet, you might need to run the dehumidifier continuously until the humidity level is reduced. For slightly damp or moderately damp rooms, running the dehumidifier for a few hours each day may be sufficient.

What happens if I use a dehumidifier that’s too small for my space?

If you use a dehumidifier that’s too small for your space, it may not be able to effectively reduce the humidity level. This could lead to issues like mold growth, discomfort, and damage to your home or belongings.

Can I use one dehumidifier for my entire house?

It depends on the size of your house and the level of humidity in different rooms. In most cases, it’s more effective to use multiple smaller dehumidifiers in different areas of your house rather than one large dehumidifier.

How do I maintain my dehumidifier?

Regular maintenance of your dehumidifier can include cleaning the filter, emptying the water tank, and checking for any signs of damage or wear. Always refer to the user manual for specific maintenance instructions for your particular model.

Leave a Comment

Your email address will not be published. Required fields are marked *