Air mover and dehumidifier calculator
A starting count of air movers and dehumidifiers for a water loss, room by room, with the equipment days to put on the estimate.
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Wet rooms
How the equipment is worked out
Air movers dry the wet walls and floor, so they are counted from wall length: one per 14 linear feet of wall in each wet room, rounded up to whole units per room. You can change the wall length per air mover to match the rule your company or the carrier uses.
Dehumidifiers dry the air in the whole drying area, so they are counted from the total volume (length × width × ceiling height of every wet room): one per 1,000 cubic feet, rounded up. Change it to match your units' rated capacity.
Equipment days are the units times the drying days (3 by default), the way drying equipment is usually billed. These are the same rules as the Water mitigation pack in vPlan AR's scope of work, which adds air mover and dehumidifier days to each room from its measurements.
Treat the result as a starting point, not a drying plan. The class and category of the water, the materials, the weather and your moisture readings decide the real setup, which should follow the drying standard you work to and be adjusted as readings come in.
Tips
- Add an air mover for each wall offset or inside corner that the counted units don't reach, and for wet cabinets or toe kicks.
- Wet carpet and pad, or a Class 3 loss with wet ceilings, needs more air movement than walls alone suggest.
- Check the dehumidifier's rating: low-grain refrigerant (LGR) and desiccant units remove far more water than a household dehumidifier of the same size.
- Log moisture readings every day: they show when equipment can come out, and they back up the days on the invoice.
Do this from a scan instead
Scan the wet rooms or draw them, tag the damage, and on Pro the Water mitigation pack in Scope adds extraction, flood cuts, antimicrobial and air mover and dehumidifier days to each room from its real measurements. The scope and cost estimate export to PDF, CSV or Excel with the codes and formulas.
Frequently asked questions
How many air movers do I need for a 12×10 room?
The walls are 44 linear feet, so at one per 14 feet that is 4 air movers. Over 3 days that is 12 air mover days. Add more for offsets, wet carpet or a heavier loss.
How do you size a dehumidifier for water damage?
Start from the volume of the drying area: length × width × ceiling height of each wet room. A 12×10 room with an 8' ceiling is 960 cubic feet, so one unit at 1,000 cubic feet each. Then check against the unit's rated capacity and the class of water loss.
How long does drying equipment stay on a job?
Often 3 to 5 days, but it depends on the materials and the readings. Equipment comes out when moisture readings reach the dry standard for each material, not on a fixed day.
Is this the IICRC standard?
No. It uses simple rules of thumb to give a starting count. Follow the drying standard and guidance you work to, and adjust the equipment to the job and your daily moisture readings.
Guides
- How to Create a Water Damage Scope-of-Work Report from a Phone ScanScan the affected rooms, tag the damage, and export a professional scope-of-work report — with floor plan, room-by-room condition schedule, and photos — straight from your iPhone.
- Mold Remediation Documentation Checklist for ContractorsMold jobs get questioned more than most. This checklist covers what to record before, during and after remediation, and how to keep it organized room by room on a measured floor plan.
- How to Get LiDAR Room Measurements into XactimatevPlan AR doesn't connect to Xactimate directly yet. Here is the reliable workflow: scan, export the Measurement Sheets, key each room into your sketch wall by wall, and check the totals.
- How to Sketch and Document a Ceiling Water Damage ClaimA ceiling stain is rarely just a ceiling. Here is how to trace the source, measure what the repair really covers, record the damage room by room and hand over a scope the carrier can follow.