Advanced hygrothermal model that solves the coupled heat, and moisture transport in building envelope systems such as walls and roofs.� The model is joint development between the Oak Ridge National Laboratory and the Fraunhofer Institute in Building Physics (IBP). WUFI-ORNL/IBP is an easy-to-use, menu-driven program for use on a personal computer which can provide customized solutions to moisture engineering and damage assessment problems for various building envelope systems. The model was specifically developed for architects, and engineers� alike. It is excellent education tool as the user can visually review the transient thermal and moisture distributions as the simulation is executed.� Screen Shots


moisture modeling, hygrothermal model, combined heat and moisture transport, building envelope performance



Expertise Required

Low level of computer literacy required; Building science fundamentals is suggested. Training is being provided at regular intervals by either ORNL or IBP.


Over 680 licensed users since the release in Feb. 2001.� Within the 8 months of the first release more than 6 universities have included this model in their Building Science Courses.


Building Envelope Consultants, Architects, Designers, Architectural Engineers, Engineering Students, Code Inspectors and Universities


A flexible graphical user interface is included that helps the user enter the building construction geometry, interior and exterior surface characteristics, material properties already exist in an hygrothermal material property database, initial conditions and interior and exterior climatic conditions. The user may enter monitor positions to investigate the localized.� The WUFI-ORNL/IBP model has been adapted to employ ASHRAE SPC 160P design inputs. The user may choose either SI or Imperial Units.


Visual distributions of both space and time variables such as temperature, relative humidity, moisture content.� Moisture content of each construction layer is plotted out as a function of time. The user can also select from a� list of output data and plot these out as well. Each selected monitor position is also available in a graphic representation. Heat and moisture fluxes are also generated.� Finally, the user may also create an animation that can be stored for presentations purposes. The user may choose either SI or Imperial Units.

Computer Platform

PC-compatible, 486 or higher; Windows 95/98/NT/2000 and a VGA or higher resolution

Programming Language



Easy to use; fast to learn; employs state of the art hygrothermal physics; includes the influence of wind-driven rain.� An excellent moisture design tool.


One-dimensional; does not include the transfer of heat and moisture by air movement. Limited material property database for North American construction materials. ORNL is currently generating material properties to enhance the database.�



Oak Ridge National Laboratory


Building Technology Center
1 Bethel Valley Road, Building 3147
Oak Ridge, Tennessee 37831-6070
United States


+1 (865) 576-3924


+1 (865) 574-9354






WUFI-ORNL/IBP is available at no cost from the web site. The user is required to maintain a valid license which is renewed each year.� This allows all users to work with the latest software version.