Validation

Before they can be widely used, simulation methods must be validated. This is done by comparing simulation results with analytical results from simple cases or experimental investigations. Partly, there also exist standards, which describe comparing validation cases.

Validation can only be performed when the initial and boundary conditions are well known, the construction of the component is well documented, and all relevant material parameters are available. Unfortunately, open literature has very few experimental studies that meet the above-described conditions for validation. For this reason, the validation examples presented below will frequently make use of unpublished experimental results.

Numerous studies have used the outdoor test area of the Fraunhofer Institute for Building Physics ( to provide well-documented measurements of the hygrothermal behavior of open-air components). The comparisons between experiments and simulations have shown that WUFI^® can accurately simulate not only laboratory tests, but also the complex processes in real parts that are exposed to actual weather conditions.

WUFI^® ProWUFI^® 2DWUFI^® PlusWUFI^® Passive

Validation of a hygrothermal whole building simulation software
Antretter, F.; Sauer, Fabian; Schöpfer, Teresa; Holm, Andreas 2011

Use of moisture-buffering tiles for indoor climate stability under different climatic requirements
Antretter, Florian; Mitterer, Christoph; Jung, Seong-Moon 2010

Coupling of dynamic thermal bridge and whole-building simulation
Antretter, Florian; Radon, Jan; Pazold, Matthias 2013

Validation reports:

All-in-One Design Tool Solution for Passive Houses and Buildings – Monthly Energy Balance and Hygrothermal Simulation
Antretter, F.; Klingenberg, Katrin; Pazold, Matthias 2013

Monthly balance based method versus transient whole building energy simulation for passive house design
Schöner, Tobias; Antretter, Florian; Radon, Jan 2013

Thermal performance of slab on grade with floor heating in a passive house
Radon, Jan; Was, Krzysztof; Flaga-Marianczyk, Agnieszka; Antretter, F. 2014

more validation reports

WUFI^® in standards and guidelines

The hygrothermal assessment of constructions with the simulation tool WUFI^® corresponds to the state of the art and to current rules of technology.

The standardized Glaser-Method doesn´t allow the evaluation of the general moisture protection, since it only estimates the risk of dew in nonhydroscopic materials, which are not capillary-active (e.g. insulations), only in winter time. Furthermore, it doesn´t include properly other moisture loads like building moisture, rainwater, and summer condensation as well as climatic and/or usage conditions that don´t fit to the usual settings in residential buildings. Therefore, hygrothermal simulation is required.

HygrothermalThermalOthers

International

ASTM International: Moisture Analysis and Condensation Control in Building Envelopes
H.R. Trechsel (Hrsg.), ASTM, West Conshohocken, PA, 2001

“The above suggests that the prescriptive rules alone will not assure that building envelopes are free of moisture problems. Accordingly, […] we must look to job specific moisture analysis methods and models for the solution to reduce or eliminate moisture problems in building envelopes. This does not mean that the traditional prescriptive rules shouild be ignored or that they should be violated without cause. They should, however, be used as starting points, as first approximations, to be refined and verified by moisture analysis.” “This chapter will describe the development of an advanced hygrothermal model called WUFI^® ORNL/IBP that is tailored for architects and building envelope designers. Its purpose is to assist during the design stage to optimize the heat and moisture performance of the envelope.
WUFI^®ORNL/IBP is an easy-to-use, menu-driven program for use on a personal computer that can provide customized solutions to moisture engineering and damage assessment for various building envelope systems.” (p. 136)

ASTM International: Moisture Analysis and Condensation Control in Building Envelopes

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Europe

EN 15026: Hygrothermal performance of building components and building elements – Assessment of moisture transfer by numerical simulation; German version EN 15026:2007

USA

2009 ASHRAE Handbook – Fundamentals

(ASHRAE Product Details)
“Computer models can analyze and predict the heat, air, and moisture response of building components. These transient models can predict the varying hygrothermal situations in building components for different design configurations under various conditions and climates, and their capabilities are continually improved. […] For many applications and for design guide development, the actual behavior of an assembly under transient climatic conditions must be simulated, to account for short-term processes such as driving rain absorption, summer condensation, and phase changes.” (p. 25.13)

2009 ASHRAE Handbook - Fundamentals

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ANSI/ASHRAE Standard 160-2009: Criteria for Moisture-Control Design Analysis in Buildings

(ASHRAE press release)
“During the last two decades, a number of computer simulation tools have been developed to predict thermal and moisture conditions in buildings and the building envelope. In addition to their use as forensic tools in the investigation of building failures, these computer models are increasingly used to make recommendations for building design in various climates. However, results obtained with these models are extremely sensitive to the assumed moisture boundary conditions. […] This standard formulates design assumptions for moisture design analysis and criteria for acceptable performance.” (p. 2)

ANSI/ASHRAE Standard 160-2009: Criteria for Moisture-Control Design Analysis in Buildings

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Germany

DIN 4108: Thermal protection and energy economy in buildings – Part 3: Protection against moisture subject to climate conditions – Requirements and directions for design and construction

WTA Codes

Code 6-1-01/D: “A guide to hygrothermal computer simulation”

Code 6-2-01/D: “Simulation of heat and moisture transfer”

Switzerland

Code “Feuchteschutz bei Flachdächern in Holzbauweise”

Sweden

Swedish Building Regulations – BBR 2011

International

ISO 6946: Building components and building elements - Thermal resistance and thermal transmittance - Calculation method (ISO 6946:2007); German version EN ISO 6946:2007

ISO 13790: Energy performance of buildings - Calculation of energy use for space heating and cooling (ISO 13790:2008); German version EN ISO 13790:2008

ISO 13791: Thermal performance of buildings - Calculation of internal temperatures of a room in summer without mechanical cooling - General criteria and validation procedures (ISO 13791:2012); German version EN ISO 13791:2012

ISO 15255: Energy performance of buildings - Sensible room cooling load calculation - General criteria and validation procedures; German version EN 15255:2007

DIN EN ISO 15265: Energy performance of buildings - Calculation of energy needs for space heating and cooling using dynamic methods - General criteria and validation procedures; German version EN 15265:2007

Germany

DIN 4108-2:2013-02: Thermal protection and energy economy in buildings - Part 2: Minimum requirements to thermal insulation

VDI 6020 - 1: Requirements on methods of calculation to thermal and energy simulation of buildings and plants - Buildings

VDI 2078: Calculation of cooling load and room temperatures of rooms and buildings (VDI Cooling Load Code of Practice)

VDI 6007 – 1: Calculation of transient thermal response of rooms and buildings - Modelling of rooms

International

DIN EN ISO 7730:2006-05: Ergonomics of the thermal environment - Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria (ISO 7730:2005); German version EN ISO 7730:2005

Europa

DIN EN 15251:2012-12: Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics; German version EN 15251:2007

DIN EN 13779:2007-09 : Ventilation for non-residential buildings - Performance requirements for ventilation and room-conditioning systems; German version EN 13779:2007

DIN EN 13829:2001-02: Thermal performance of buildings - Determination of air permeability of buildings - Fan pressurization method (ISO 9972:1996, modified); German version EN 13829:2000

Last Update: January 18, 2023 at 14:28

Validation

Validation examples:

Validation reports:

Validation examples:

Validation reports:

Validation reports:

Validation reports:

WUFI® in standards and guidelines

WUFI^® in standards and guidelines