WUFI Analysis

What is it? Why it's important?

At Partel we offer WUFI® analysis on request to ensure that the completed project is functioning correctly. 

Incorrect installation or lack of appropriate membranes can cause issues with insulation functioning as specified leading to lower U Values, dampness, and structural damage.

What is WUFI®

WUFI® - Oak Ridge National Laboratory (ORNL)/Fraunhofer Institute for Building Physics (IBP) is a menu-driven PC program which allows realistic calculation of the transient coupled one-dimensional heat and moisture transport in multi-layer building components exposed to natural weather. WUFI-ORNL/IBP is based on the newest findings regarding vapour diffusion and liquid transport in building materials. The underlying model has been validated for over 25 years.


Besides the thermal properties of a building component and their impact on heating losses, its hygric behavior has to be considered, too. Permanently increased moisture content in the component may result in moisture damages. Elevated surface moisture levels in living rooms can lead to hygienic problems and health risks due to mould growth. In addition, thermal and hygric behavior of a building component are closely interrelated as well as an increased moisture content favors heat losses. The thermal situation affects moisture transport. Therefore, both have to be investigated together in their mutual interdependence; the research field of hygrothermics is dealing with these problems.

Out of Date: Dew-Point (Glaser)

The Dew-Point method as detailed in American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) handbook has been a common method to assess the moisture balance of a building component by considering vapour diffusion transport in its interior. However, this method does not allow for the capillary moisture transport in the component, nor for its sorption capacity, both of which reduce the risk of damage in case of condensation. Furthermore, since the method only considers steady-state transport under heavily simplified boundary conditions, it cannot reproduce individual short-term events or allow for rain and solar radiation. It is meant to provide a general assessment of the hygrothermal suitability of a component, not to produce a simulation of realistic heat and moisture conditions in a component exposed to the weather prevailing at its individual location.


The menu-driven PC program WUFI-ORNL/IBP developed by the Holzkirchen branch of the Fraunhofer IBP and ORNL validates using data derived from outdoor and laboratory tests, allows realistic calculation of the transient hygrothermal behaviour of multi-layer building components exposed to natural climate conditions.