Inputs
Use conditions near the wet framing, not at the thermostat.
Example data table
Sample scenarios to sanity-check your inputs.
| Scenario | Temp (°C) | RH (%) | Airflow | Dehu | Size | MC (start→target) | Typical outcome |
|---|---|---|---|---|---|---|---|
| Indoor, active drying | 22 | 55 | Fan | Refrigerant | 2×4 | 28% → 16% | Several days for many projects |
| Humid, limited equipment | 18 | 78 | Normal | None | 2×6 | 26% → 18% | Often a week or more |
| Cold space, sealed surfaces | 10 | 70 | Still | None | 4×4 | 24% → 16% | Slow drying; control RH to progress |
Use a moisture meter and multiple locations per bay to confirm.
Formula used
This tool estimates drying with an exponential approach-to-equilibrium model: MC(t) = EMC + (MC₀ − EMC) · e^(−k·t). Solving for time gives t = ln((MC₀−EMC)/(MCₜ−EMC)) / k.
EMC is an estimated equilibrium moisture content based on relative humidity and temperature. k is a drying constant adjusted for airflow, ventilation, dehumidification, surface finish, member thickness, and a small species group factor.
Results are planning estimates. Always verify with field measurements and project requirements.
How to use this calculator
- Measure temperature and relative humidity close to the wet framing.
- Enter initial and target moisture content from a meter reading.
- Select equipment and conditions: fans, ventilation, and dehumidification.
- Choose member size and quantity to estimate water removal.
- Review results and recommendations, then export a report if needed.
If the target moisture is below the estimated EMC, drying will stall. Lower humidity, increase temperature safely, or add dehumidification to reach the target.