How to calculate air movers?

To calculate how many air movers you need for water damage drying, professionals use the IICRC S500 standard which provides formulas based on square footage and linear feet of walls. The basic calculation is one air mover per 150 to 300 square feet of affected floor area for standard Class 1 and Class 2 water losses. For example, a 600 square foot basement would need 2 to 4 air movers for floor drying. The more precise method adds wall drying, one air mover per 10 to 15 linear feet of wet wall, angled at 45 degrees. So a room that is 20 by 30 feet has 100 linear feet of wall, which would need about 7 to 10 air movers if all walls are wet and you want fastest drying. You also need to factor in room shape, with more air movers needed for L-shaped rooms to ensure air reaches corners. You must also calculate electrical capacity, as each air mover draws 2 to 10 amps, so you cannot put more than 3 to 4 large units on a single 15 amp household circuit without tripping breakers. For heavy saturation or Class 3 and Class 4 losses with hardwood or plaster, you may need one air mover per 50 to 100 square feet. A simple homeowner rule is one air mover per affected room plus one extra for every 150 square feet beyond that, plus one dehumidifier per 1000 square feet to remove moisture from the air.