Air Mover and Dehumidifier Calculator
Get a starting count of air movers and LGR dehumidifier capacity for a water loss, from wet floor area, wall length, ceiling height and loss class. Written for restoration techs setting equipment, and for property managers who want to understand a drying invoice.
Free, no sign-up. Runs in your browser; nothing you type is stored unless you choose to email yourself the results.
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Three steps, about a minute
Step 1
Enter the Wet floor area and the Affected wall length from your moisture map.
Step 2
Enter the Ceiling height and pick the Water loss class you assigned on site.
Step 3
Place equipment to match the results, then adjust as daily moisture readings come in.
How the air mover calculator works
Air movers are two counts added together: affected wall length ÷ 14, rounded up, plus wet floor area ÷ 60, rounded up. Dehumidification starts with the room's cubic footage (floor area × ceiling height), divided by a class factor of 100 for Class 1, 40 for Class 2 or 30 for Class 3. The answer is LGR capacity in pints per day, and the last line divides it by 70 to count 70-pint units, rounded up. A 400 sq ft Class 2 loss with 60 linear ft of wet wall and 8 ft ceilings starts at 12 air movers, 80 pints per day and two 70-pint units. These are common guideline factors for LGR units only. Wet ceilings, Class 4 materials and desiccant setups are not covered. Verify with daily moisture readings and follow IICRC S500 and carrier requirements.
| Wet floor area | 400 sq ft |
|---|---|
| Affected wall length | 60 linear ft |
| Ceiling height | 8 ft |
| Water loss class | Class 2 (significant) |
| Air movers (starting point) | 12 |
|---|---|
| LGR dehumidifier capacity | 80 pints/day |
| 70-pint units | 2 |
Starting estimates using common guideline factors for low-grain-refrigerant dehumidifiers. Adjust on site with moisture readings.
Using the numbers like a pro: tips for restoration companies
Document why each piece of equipment is on the job. Adjusters question air mover counts, and a written calculation with photos and moisture logs makes your invoice easier to defend.
Pull equipment as areas reach dry standard, and log each removal. Daily readings that show progress justify each day of equipment charges and keep the job moving toward rebuild.
Load dehumidifiers before you leave the shop. Knowing a 400 sq ft Class 2 loss needs two 70-pint units saves a second trip and gets drying started the same day.
Put a calculator like this on your own website
In an emergency, homeowners need your phone number more than a calculator. This tool fits better on pages aimed at property managers, adjusters and insurance agents, the people who send you repeat work. Show the equipment estimate, then ask for contact details to send a written scope. Keep a 24/7 call button beside it for live losses. We can build a version that routes each request to your on-call tech.
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Air Mover and Dehumidifier Calculator questions
How many air movers do I need per square foot?
A common starting guideline is one air mover for every 50 to 70 sq ft of wet floor, plus one for every 10 to 16 linear ft of wet wall. This calculator uses 60 sq ft and 14 ft. Wet ceilings, insets and offsets can need more, and moisture readings decide the final setup.
What is an LGR dehumidifier?
LGR stands for low grain refrigerant. These units chill the air more deeply than standard refrigerant dehumidifiers, so they keep pulling moisture out even as the air gets drier. That makes them a common choice for structural drying. Capacity is rated in pints per day, the figure this calculator estimates.
How long does it take to dry a water-damaged room?
It depends on the materials, class of loss, equipment and how quickly drying started. A few days is common for a typical room, while saturated walls, hardwood or concrete can take longer. Daily moisture readings, not the calendar, show when materials reach their dry standard.
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