Restoration Lab · Free tool

Drying goal calculator

Set a drying goal that will not re-wet the building — a maximum GPP and RH that keep the room’s dew point safely below the coldest affected surface.

Set a drying goal that won’t re-wet the building. Hold the room’s dew point ~5°F below the coldest affected surface so moisture stops condensing there.

59.8max GPP goal
37%max RH @ 82°F
Keep the room’s dew point at or below 53°F (5°F under the 58°F surface). Drive the dehu exhaust below this GPP and the surface dries instead of sweating.

Why a drying goal is a dew-point goal

The whole point of dehumidification is to hold the air’s dew point below every surface in the room. If the dew point creeps above a cold surface, water condenses there and you create new damage even while the equipment runs. Set the goal a few degrees under the coldest surface and drive the dehu exhaust below it.

Preventing secondary damage

Secondary damage — swollen trim, sweating windows, mold behind baseboards — usually comes from a dew point that was never controlled, not from the original loss. A written drying goal in GPP gives the crew a target they can verify with a meter every day.

Frequently asked

What is a drying goal in restoration?

A drying goal is the target humidity — expressed as a maximum GPP and RH — that keeps the room dry enough to pull moisture from materials without letting the dew point rise to a cold surface and condense.

How do I set a drying goal?

Find the coldest affected surface temperature, set the target dew point a few degrees below it, and convert that to a maximum GPP and RH for the room. Keep the dehumidifier exhaust below that GPP.

What causes secondary damage during drying?

Secondary damage is usually caused by an uncontrolled dew point — moisture condensing on cold surfaces like windows, slabs, and exterior walls — rather than by the original water loss. A drying goal prevents it.

More free tools

Psychrometric calculatorDehumidifier sizing calculatorAll drying tools →

This knowledge, built into the software

RestoredOS runs the whole job on the same field knowledge behind these tools — drying logs, moisture mapping, scope, and billing.

Try the live demoSee RestoredOS