Dehumidifier Sizing Calculator
Find the right dehumidifier capacity for your space. Properly sizing your unit ensures efficient moisture removal and energy use. This calculator provides an estimate based on common factors.
How to Use This Calculator
Follow these simple steps to get your dehumidifier size recommendation:
- Enter Room Area: Input the square footage (or square meters) of the space you need to dehumidify. If you only have length and width, multiply them to get the area.
- Select Dampness Level: Choose the option that best describes the current conditions in your room. This is a key factor in determining capacity.
- Slightly Damp: Feels a bit stuffy, occasional musty smell, humidity around 50-60%.
- Moderately Damp: Air often feels clammy, musty odors are common, perhaps some condensation on windows, humidity around 60-70%.
- Very Damp: Visible mold or mildew spots, walls feel damp, strong musty or earthy smells, humidity around 70-80%.
- Extremely Wet: Standing water, seepage, extensive mold growth, humidity above 80%.
- Check Additional Factors:
- Tick “Is this a basement or crawl space?” if applicable, as these areas often require more dehumidification.
- Tick “Room has frequent laundry/showers?” if the space includes a washing machine or is a bathroom with regular shower use, as these activities add significant moisture.
- Calculate: Click the “Calculate Size” button.
The result will show the recommended dehumidifier capacity in pints of moisture removed per 24 hours. This is the standard rating for dehumidifiers.
Understanding Your Dehumidifier Size
The capacity of a dehumidifier is measured in how many pints of water it can remove from the air in a 24-hour period. For example, a “30-pint dehumidifier” can remove up to 30 pints of moisture per day under specific test conditions (typically 60% relative humidity at 80°F / 26.7°C, though newer standards test at 65°F / 18.3°C and 60% RH).
- Too Small: An undersized unit will run constantly without effectively lowering humidity, wasting energy and failing to solve the problem.
- Too Large: While a slightly oversized unit is often better than undersized, a grossly oversized unit might cycle on and off too frequently (short-cycling), which isn’t ideal for longevity or consistent humidity control. However, for very damp conditions, erring on the larger side is generally recommended.
Our calculator provides a baseline. If your conditions are severe or you’re on the borderline between sizes, it’s often wise to choose the next size up. Also, consider factors not in this basic calculator, like the number of people in the space, local climate, and how well-sealed the room is.