Last Updated: February 27, 2024
High humidity can make your home feel musty and unbearable and adversely impact electronics, furniture, clothing, wallpaper. Left unchecked, moisture buildup can lead to mold and mildew growth, water damage, musty odors, warped wood, and peeling paint.
A dehumidifier is an energy-efficient solution that improves indoor air quality, keeps your house comfortable, and provides a continuous flow of fresh, dry air. Dehumidifiers prevent rooms from smelling musty and protect your valuables, clothes, furniture, electronics, and other possessions. These appliances regulate humidity by drawing moisture from the air. A fan pulls the moist air into the device through coolant-filled coils, which use condensation to remove dampness from the air. The dehumidifier releases the warmer, dryer air back into the room while the water is collected in a removable drip pan or reservoir or is circulated out of the unit.
Dehumidifiers come in different shapes and sizes, from mini dehumidifiers that can dehumidify a closet or bathroom to one-room units suitable for your bedroom, nursery, or basement, and finally, whole-house solutions that tie into the home’s HVAC system and dehumidify the whole house. It is essential to select the right dehumidifier per your needs. Check whether your entire house is overly humid or the issue confined to a particular area? The scope of the problem determines the nature of the solution. A smaller than required appliance might not entirely remove the humidity. At the same time, a larger-than-required dehumidifier may leave you with a hefty energy bill and is too loud to use in the bedroom.
How To Choose The Right Size Dehumidifier
Moisture Removal Capacity
Dehumidifiers are measured on their total moisture removal capacity, rated in pints of moisture removed per day (24-hour period), and also known as pints per day or PPD. These units come in different capacities, from smaller models that can remove 20 ppd to large commercial units that take out more than 100 units. A pint amounts to 1/8 of a gallon. A 70-pint dehumidifier can absorb almost 9 gallons of water from the air throughout the day at your place.
All dehumidifiers sold in the USA must conform to the Department of Energy (DoE) standards. The department certifies dehumidifiers on two primary performance metrics:
Pint Capacity – The amount of water removed in 24 hours at test conditions.
Energy Efficiency – How many liters of water a dehumidifier can remove per kilowatt per hour of energy consumed.
As per the 2019 testing standards, dehumidifiers are tested at 65 degrees F and 60% humidity, which is 15 degrees lower than the earlier 2012 standards. Since less water vapor is removed from cooler air, it also reduces the number of pints each dehumidifier can remove.
For calculating energy efficiency, the DoE introduced a new metric, Integrated Energy Factor (IEF), that considers the energy consumed when the dehumidifier fan is running, but the refrigeration system is off. As per the department, this is a more accurate representation of power consumption.
Room Size
Start by measuring the space where you want to keep the dehumidifier with the help of a tape. Take the room’s length and width and multiply them to calculate the square footage of the area. For instance, a 20 feet long and 15 feet wide room has a square footage of 300 square feet.
The Association of Home Appliance Manufacturers (AHAM) has come with directives on dehumidifiers’ capacity for different relative humidity and area sizes.
30-Pint Dehumidifier – These dehumidifiers can effectively cover an area between 500 to 1,500 square feet where the relative humidity is higher than 85%.
50-Pint Dehumidifier – These dehumidifiers are suitable for extremely humid, mid-sized areas with constant musty and damp smells. These size dehumidifiers are recommended for areas up to 2000 square feet that feel damp and smell musty all the time.
70-Pint Dehumidifier – These dehumidifiers are recommended for areas larger than 2000 square feet, such as houses with crawl space, commercial buildings, having highly humid conditions. They’re also suitable for 2,500 and 3,000 square feet with more than 85% relative humidity.
Climatic Conditions
Please note that AHAM sizing chart does not consider the average temperature of the space. Selecting a dehumidifier based on capacity and area is not enough, and you should also keep in mind the climatic conditions. Check how much dampness is there in your space.
This table indicates what size of the dehumidifier is suitable for what area (slightly damp 50-60%)
| Space Area (in Sq. ft) | Pint capacity |
| 0-300 sq. ft. | 20 Pints |
| 300-500 sq. ft. | 25 Pints |
| 500-800 sq. ft. | 35 Pints |
| 800-1200 sq. ft. | 40 Pints |
| 1200-2000 sq. ft | 50 Pints |
| 2000-2500 sq. ft | 60 Pints |
A dehumidifier with the rated capacity for requisite square footage would be sufficient if it remains slightly damp. However, if you have a place that remains extremely wet, choosing a somewhat larger capacity unit is ideal. For example, a dehumidifier that removes 60 pints of water when the air is saturated is less powerful than a model that removes 60 pints of water at standard room conditions (65 degrees F, 60% humidity).
Additional Things to Consider
Humid climate: If you live in a humid environment, the relative humidity indoors will be higher. You can add 10 pints to your dehumidifier.
Cold Basement: If you have a cold basement, it is ideal to add 10 pints to the overall size of the dehumidifier as the appliances have to work harder in colder environments.
See also: Dehumidifiers for Basements
Washing machine or dryer: If you live in a smaller apartment, the washer or dryer is likely placed close to your living space. This may increase the humidity — add 5 pints.
Dehumidifier placed in the kitchen: The humidity rises when you are cooking. If you want to use the dehumidifier in the kitchen, add 5 pints to its moisture removal capacity to efficiently handle the condensation.
Usage of AC: If you often use the AC during summer, you can select a slightly smaller dehumidifier than the advertised capacity. AC ad dehumidifiers can effectively work together to create a dry and relaxed environment.
Pets: If you have pets at the house, especially cats or dogs with fur, keeping humidity levels low is essential. Thanks to the extra fluff, pets have a challenging time cooling down during the summer, and they also run the risk of heart strokes. Hence it is essential to select a higher capacity dehumidifier.
The number of occupants – Human beings release moisture in the atmosphere whenever they breathe or talk. Consider a dehumidifier with a larger capacity if many people occupy an area. For every four to five people, you should add five pints to your calculations.
Bathrooms: Bathrooms attract bacteria and mold more than any other room. Washing your hands, running steamy showers, and flushing the toilet all increase the RH level of your bathroom. For a bathroom dehumidifier, it is best to add five to ten pints to your calculations.
Energy Efficiency: Energy Star-certified dehumidifiers use about 15% less energy than conventional units; this means saving approximately $175 over the life of the dehumidifier, not to mention avoiding roughly 2,800 pounds’ worth of greenhouse gas emissions.
Refrigerant vs Desiccant
There are two basic types of dehumidifiers: Refrigerant and Desiccant.
If you experience sweltering and humid temperatures with high humidity that remains above 70%, you need a robust dehumidifier. For this type of environment, a refrigerant model is highly effective at removing large amounts of moisture and can work in higher temperatures. Refrigerant dehumidifiers (also known as compressors) can remove between 10 and 25 liters of moisture per day. However, refrigerant dehumidifiers cannot work efficiently in colder climates. As the temperature falls below 60 degrees Fahrenheit, they run the risk of ice forming on the liquid coils. This can lead the dehumidifier to waste energy and also damage the unit from the inside.
Desiccant dehumidifiers are made of desiccant, which easily attracts and holds water vapor. Desiccant dehumidifiers are well-suited for removing moisture at a low temperature and low humidity level. These are recommended for colder environments like garages, conservatories, and basements as they work at lower temperatures. Since these units do not employ cooled coils to condense and collect water similar to a refrigerant dehumidifier, they are more efficient in cold environments. Desiccant dehumidifiers are quieter as they don’t have a compressor and are more energy-efficient and effective at drying already dry air.
Frequently Asked Questions
What Size Dehumidifier Do I Need for a Basement?
Basements have higher relative humidity and average temperature, which may lead to mold and mildew growth. It can also make the house’s walls weaker over time and put the whole house at risk. For example, if your basement has a square footage of 500 sq. ft., relative humidity at 80%, and an average temperature of 70°F. In this case, as per the AHAM standards, you would need a 50-60 pint dehumidifier (old standard) or a 25-30 pint dehumidifier (as per the new standard).
What Size Dehumidifier is recommended for a Whole House?
These are the sizes of a small house. For example, if the square footage of the house is 1200 sq. ft., relative humidity is 65%, and an average temperature of 70°F. In this case, as per the AHAM standards, you would need a 70-pint dehumidifier (old standard) or a 50-pint dehumidifier (according to the new standard). If you experience higher humidity or the house is larger, you may want to consider the high-capacity commercial dehumidifiers.
Can I use a 70-Pint Dehumidifier when Only 30 Pints is required?
There is no harm in running a large dehumidifier in a small space; however, it may be louder and increase power consumption unnecessarily, leading to higher energy costs leading to energy wastage. On the other hand, if it is only slightly larger( 50 in place of 30), it will work more quickly to draw moisture out of the air so that you can turn it off sooner. This means that it will save more energy.
Shall I Install a Dehumidifier in Each Room?
Installing a dehumidifier based on the number of rooms can prove tricky because you have to account for the size of each room. It is better to calculate the overall area of your house and then position the dehumidifier accordingly, so it provides optimal coverage. You may need more than one dehumidifier for efficient coverage in an extensive or multi-level home.
Where Should I Place the Dehumidifier for the Best Results?
It is ideal to set up your dehumidifier in the room where it is needed the most, generally the room that remains damp at any given time. Such spaces include bedrooms, basements, laundry rooms, crawlspaces, and areas that typically exhibit moisture problems. For specific positioning, you should place the dehumidifier on the floor and sections of the room where moisture dominates the air.
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