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MOIST: A computer program for predicting heat and moisture transfer in building envelopes.

MOIST is a user-friendly, computer program that predicts the one-dimensional transfer of heat and moisture. With MOIST, you will be able to easily define a wall, cathedral ceiling, or low-slope roof construction. You will subsequently be able to investigate the effects of various parameters on the moisture accumulation within layers of the construction. For example, you will be able to conduct computer runs for different U.S. and Canadian cities, thereby investigating the effect of climate on moisture accumulation. You will be able to determine if a vapor retarder is needed, and if needed, where it should be placed relative to the other materials. MOIST allows the user to vary the building materials and their relative placement and predicts the resulting moisture accumulation within each as a function of time for the selected climate. An enhanced capillary pressure curve has been incorporated into the MOIST model. MOIST permits the evaluation of the effect of the water-vapor resistance offered by paint layers, wallpaper, and vapor retarders. Finally, MOIST can be used to generate guidelines and practices for controlling moisture.


Version 4:

MOIST 3.0 has been updated to version 4.02 by Ray W. Herrick Laboratories, Purdue University, and can be found HERE.


Version 3:

MOIST 3.0 was last modified in 1997 but is still being made available here.

Note: NIST is providing this software as a service to interested parties, but we are no longer able to provide technical support. We apologize for any inconvenience. Users have indicated trouble using ver. 3 of the software on modern operating systems. We recommend that you download ver. 4 noted above. If you need assistance reading the manual please contact Webmaster

Lead Organizational Unit:



Theory of MOIST developed by:
Douglas M. Burch

Visual Basic Program developed by:
Joseph Chi, PhD, PE
University of District of Columbia
Washington, DC 20008