Right-size drying equipment for basements, slabs, and framing. Plan faster schedules with safer humidity targets. Download reports, share with teams, and reduce rework today.
| Scenario | pints/day | units |
|---|---|---|
|
Basement slab curing
45 m² ×
2.4 m,
80→50% RH,
0.5 ACH
|
97.8 | 2 × 70 |
|
Flood restoration room
30 m² ×
2.8 m,
85→45% RH,
1.5 ACH
|
378.0 | 5 × 90 |
|
New framing with ventilation
900 ft² ×
9 ft,
70→50% RH,
1 ACH
|
82.1 | 2 × 70 |
This calculator estimates daily moisture removal by combining four loads:
Key relationships:
For best accuracy, verify with hygrometers and material moisture meters. Tighten containment and airflow first, then fine-tune dehumidifier quantity.
Dehumidifiers are labeled in pints per day at controlled lab conditions. On construction drying, colder slabs, short cycling, and airflow limits can cut performance by 20–40%. Use the efficiency allowance to convert nameplate capacity into removal in practice, and lower it further when room temperatures drop below 18°C.
The calculator converts floor area and ceiling height into room volume, then estimates moisture in the air at current and target humidity using humidity ratio. The pull-down load equals dry-air mass times the humidity-ratio difference, divided by the hours you want to reach target. A fast pull-down window (8–16 hours) suits response work; longer windows (24–48 hours) often fit curing slabs and new framing.
Air changes per hour (ACH) can become the biggest driver in humid weather. The model compares outdoor humidity ratio to the indoor target and multiplies by exchanged air volume per day. Typical ranges: 0.3 ACH for tight containment, 0.7 ACH for interiors, and 1.0–2.0 ACH when doors, window fans, or exhaust systems run. Sealing openings can reduce required capacity better than adding another unit.
Wet materials release water for days after flooding, washing, plastering, or curing. Enter total water expected to evaporate, then spread it across drying days to get liters per day. As a guide, film water on 50 m² can exceed 30–60 liters. Occupancy is added using about 0.06 kg per hour per worker, so three workers at eight hours add roughly 1.4 liters daily.
Total daily demand is the sum of pull-down, infiltration, materials, and people, then increased by a safety factor and divided by efficiency. The result is shown in liters and pints per day, plus an estimated number of standard units (35–250 pints/day). Exporting CSV and PDF supports job logs, equipment checkout, subcontractor coordination, and moisture-control signoffs.
Choose the manufacturer’s rated pints/day for the model you plan to deploy. If conditions are cool, add a lower efficiency (60–75%) rather than inflating the nameplate rating.
Enable it when doors or windows are open, exhaust fans run, temporary ventilation is used, or the space is leaky. Outdoor humidity can dominate the daily load, especially in humid seasons.
Use project records, moisture mapping, or a conservative allowance. For washed or flooded rooms, start with a rough liters/gallons estimate and refine daily using humidity trends and material meter readings.
Many drying plans aim for 40–55% RH to limit mold risk while allowing evaporation. Sensitive finishes or adhesives may require tighter limits; follow manufacturer guidance and local standards.
Dehumidifiers remove less water in cooler air, and evaporation from surfaces slows. If the space is below about 18°C, reduce the efficiency input, add heat, and improve airflow to stabilize performance.
A small buffer is fine, but heavy oversizing can raise energy use and cause short cycling. If results look high, first reduce ACH, seal openings, and add air movers, then reassess with fresh readings.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.