Tool
Estimate how many dehumidifiers your space needs using the IICRC S500 restoration method. Enter your room dimensions and the water-damage class, and choose the dehumidifier capacity you plan to use.
The calculator finds your room volume (length × width × height in cubic feet), then applies the IICRC S500 class factor — a divisor that reflects how much water must be removed for each water-damage class. That gives the total pints per day (PPD) of moisture removal required. Dividing by your chosen unit's PPD rating gives the number of dehumidifiers.
Class factors used: Class 1 ÷100 · Class 2 ÷40 · Class 3 ÷30 · Class 4 ÷50 (specialty). These are planning figures — temperature, airflow and materials affect real-world drying.
Refrigerant and LGR (low-grain refrigerant) units are rated in pints per day and suit warm, humid air — this calculator sizes those. Desiccant units are rated by airflow (CFM) and perform better in cooler conditions or when you need very low humidity; for those, call us and we'll size by CFM and grain depression.