Welcome to the Dew Point Calculator

Use the sliders to explore combinations of temperature (T), relative humidity (RH), and dew point (DP) to compare the preservation quality of your environment. Knowing the dew point can help achieve long-term preservation of collection materials for libraries, museums, and archives.To report on your storage environment use the PEM2® to record data and eClimateNotebook® to analyze it.

Click to Solve for:
Temperature
68
% RH
50
Dew Point
49
Preservation Evaluation
Type of
Decay
Environment
Rating
Preservation
Metric
Natural
Aging
RISK
PI
44
Mechanical
Damage
OK
% EMC
9.3
Mold
Risk
GOOD
Days to
Mold
No Risk
Metal
Corrosion
OK
% EMC
9.3
Record and Compare Values
T
RH
DP
PI
Days to Mold
EMC
Temperature Scale:     °F °C

The dew point temperature determines what combinations of temperature and RH will be possible in the storage environment. At a constant dew point, when the temperature goes up, the RH goes down and when the temperature goes down, the RH goes up. Controlling the dew point is key to managing the risk of material decay. What's your dew point? If you know the T & RH in your space you can use the DP Calculator to get the DP. If your building does not have humidification or dehumidification, the indoor dew point is the same as the outdoor dew point.

PEM2 Datalogger eClimateNotebook IPI's Guide to Sustainable Preservation Practices for Managing Storage Environments