Dehumidifier Size Calculator
Find the right capacity (Pints per 24 Hours) for your space.
Recommended Capacity:
How to Choose the Right Dehumidifier Size
Choosing the correct dehumidifier size is critical for maintaining air quality and preventing structural damage to your home. Unlike many household appliances, dehumidifiers are sized based on the amount of moisture they can remove in a 24-hour period, measured in "pints per day" (PPD), rather than the physical dimensions of the unit itself.
To determine the correct size, you must consider both the total square footage of the space and the existing moisture levels. If you select a unit that is too small, it will run constantly without ever reaching the desired humidity level, leading to high energy bills and premature motor failure.
Understanding Moisture Levels
- Moderately Damp (50-60% RH): The air feels humid and there is a faint musty odor only during humid weather.
- Very Damp (60-70% RH): The area always smells musty and you may see damp spots on walls or floors.
- Wet (70-80% RH): Moisture is visible on walls or floors, and the space feels consistently "sticky" or heavy.
- Extremely Wet (80-100% RH): You see standing water or seepage, and mold/mildew growth is visible.
Example Calculation
If you have a basement that is 20 feet by 30 feet (600 square feet) and it feels "Very Damp," a standard calculation might look like this:
- Base Capacity: 12 pints for the first 500 sq. ft.
- Additional Load: 5 pints for the remaining 100 sq. ft. increment.
- Total Requirement: Approximately 17-20 Pints Per Day.
Note: It is usually better to "oversize" a dehumidifier. A larger capacity unit will reach the target humidity faster and cycle off, which is more energy-efficient than a smaller unit running 24/7.