Choose the Size of a Dehumidifier
Dehumidifiers are appliances that can be placed within rooms in a home to remove excess moisture from the air. When you choose a dehumidifier, selecting the right size is crucial to how effective the performance of your dehumidifier will be for that room or area. For example, large basements with high humidity levels may require large or multiple dehumidifiers; whereas smaller bathrooms may only require one small dehumidifier. Continue reading to learn how to choose a dehumidifier based on your needs.
Steps
- Use a hygrometer to gain an accurate humidity reading of the room or area you want to dehumidify.
- A hygrometer can be purchased from any retail store that specializes in home repair and will provide you with the percentage of humidity that resides in a specific room or area.
- Use specific characteristics of the room to determine its humidity levels if you do not have access to a hygrometer.
- If the room is extremely wet and contains standing water or puddles of water, the humidity will be between 90 and 100 percent and is considered "extremely wet."
- If the room smells and feels wet and contains visible mold, mildew, leaks, and water stains, the humidity level will be between 80 and 90 percent and is classified as "wet."
- If the room feels very damp and you can clearly smell mold and mildew, the humidity levels will be between 70 and 80 percent and is known as "very damp." You may or may not see visible water stains on walls and on the floor.
- If the room only smells musty in damp or humid weather, the relative humidity will be between 60 and 70 percent and is considered "moderately damp."
- Determine your air changes per hour (ACH) to calculate the airflow needed to properly dehumidify your room.
- If your humidity level is extremely wet or between 90 and 100 percent, your ACH will have a value of "6."
- If your humidity level is considered "wet" or between 80 and 90 percent, your ACH will be a value of "5."
- When your humidity in the room is considered to be "very damp" and falls between 70 and 80 percent, your ACH will have the value of "4."
- Moderately damp humidity levels that fall between 60 and 70 percent will have an ACH value of "3."
- Calculate the amount of square feet present in the room or area that you need to dehumidify.
- Measure the length and width of your room using a ruler or tape measure.
- Multiply the length and width values to figure the room's square footage.
- For example, if a room is 8 feet (2.43 meters) by 9 feet (2.74 meters), the total square footage will be 72 square feet (6.68 square meters).
- Calculate the amount of cubic feet in the room you need to dehumidify by taking the height of the room and multiplying that value by the amount of square feet.
- For example, if there are 72 square feet (6.68 meters) in a room and the height of the room is 8 feet (2.43 meters), the measurement will be 576 cubic feet (16.31 cubic meters).
- Determine the amount of airflow or cubic feet per minute (CFM) you will need in order to dehumidify the room using your cubic feet and ACH values.
- Multiply the cubic feet value by the ACH and divide the result by the number 60.
- For example, if your measurement is 576 cubic feet (16.31 cubic meters), and your room is considered "extremely wet," multiply 576 by 6 for a result of 3456. Divide 3456 by 60 for the amount of airflow you need, which is 57.6 cubic feet (1.63 cubic meters) per minute.
- Determine the pints of moisture you need extracted from the air on a daily basis to properly dehumidify your room.
- For moderately damp conditions, you will need dehumidifiers that can extract 10 pints (4.73 liters) of water within 500 square feet (46.45 square meters). For every additional 500 square feet (46.45 square meters), add 4 pints (1.89 liters). For example, for rooms that are 1500 square feet (139.35 square meters), you will need a dehumidifier that can extract 18 pints (8.51 liters) of water.
- For very damp conditions, buy dehumidifiers that can extract 12 pints (5.67 liters) of water within 500 square feet (46.45 square meters). For every extra 500 square feet (46.45 square meters), add 5 pints (2.36 liters).
- For wet conditions, choose dehumidifiers that can collect 14 pints (6.62 liters) of water within 500 square feet (46.45 square meters). Add 6 pints (2.83 liters) for every additional 500 square feet (46.45 square meters).
- For extremely wet humidity conditions, buy dehumidifiers that extract 16 pints (7.57 liters) of water from the air within 500 square feet (46.45 square meters). Add 7 pints (3.31 liters) for every extra 500 square feet (46.45 square meters).
- Buy a dehumidifier that can support your CFM and pints requirements.
- Read the manufacturer labels and boxes for dehumidifiers to determine the correct size you need to buy.
- If your CFM levels are much higher than the CFM levels supported by dehumidifiers you see for purchase, you may need to buy multiple units to properly dehumidify your space.
- If your CFM levels fall between a range of CFM levels supported by dehumidifiers, you may want to buy a unit with a higher CFM than what you need and run it less often.
Things You'll Need
- Hygrometer
- Ruler or tape measure
