What Size Dehumidifier for an 800 Square Foot Basement?

If you have an 800-square-foot basement that is very moist, a dehumidifier will remove much of the moisture and reduce that musty odor that is so overpowering. However, you need to buy the appropriate sized humidifier, and the size needed is not straightforward because you have to consider several variables.

Dehumidifier Sizing

Dehumidifiers are not sized by square footage alone, although the manufacturer will state the size of the area the dehumidifier can accommodate effectively. Humidifiers are sized by the number of pints of moisture the unit can remove in a 24-hour period. This measurement is not always directly related to square footage, because other variables impact the amount of moisture in the air of a particular space. To the homeowner making the purchase, it is sometimes difficult to know how many pints of moisture you need to remove. So, a few more guidelines are needed to determine the appropriate sized dehumidifier.

Moisture Content

The moisture content of your room is perhaps the most important variable to consider when choosing a dehumidifier for your 800-square-foot basement, because larger humidifiers are necessary to handle very damp areas. Smaller dehumidifiers will do an adequate job in basements with lower humidity and less moisture. Manufacturers state the number of pints of moisture a unit removes at certain humidity levels, measured by RH (relative humidity). This is your guideline to choosing the appropriate unit. For instance, one unit may remove 100 pints of moisture at 80 degrees Fahrenheit and 80 percent RH.

Room Size

Manufacturers refer to the maximum room size that its product can accommodate. For instance, a certain model may handle spaces up to a certain size. Many large units handle up to 2,500 square feet, while smaller units handle spaces up to 1,000 square feet. If your basement is 800 square feet, and moderately damp, a small unit that removes between 50 and 70 pints is ideal. Even in extremely damp basements of this size, only about 23 pints of moisture need to be removed to keep the area dry. However, because humidifiers have control mechanisms, buying a large humidifier to be certain you have enough power may be the right choice.

More Variables and Figuring Your Needs

Sometimes additional variables, such as consistent leaks or changing exterior moisture in your soil, increase your basement moisture content. Because it is so difficult to calculate the effect all of these variables, many homeowners contact a repair man or contractor to get a professional estimate. While this costs money, it should help specify the type of unit with enough power to solve your moisture problem. A professional with experience is better suited to consider all of these variables.