WINDOW 6 and THERM 6 Research Versions are software programs developed at Lawrence Berkeley National Laboratory (LBNL) for use by manufacturers, engineers, educators, students, architects, and others to determine the thermal and solar optical properties of glazing and window systems.

WINDOW 6 and THERM 6 are significant updates to LBNL's WINDOW 5 and THERM 5 computer program because of the added capability to model complex glazing systems, such as windows with shading systems, in particular venetian blinds. Besides a specific model for venetian blinds and diffusing layers, WINDOW 6 also includes the generic ability to model any complex layer if the Transmittance and Reflectance are known as a function of incoming and outgoing angles.

The algorithms used in these versions of the programs to determine the properties of windows with shading layers are relatively new and should be considered as informative but not definitive.

As such, for windows with shading layers, the results are intended for research purposes only. Pending further validation efforts, results for windows with sh ading layers should not be used for NFRC certified calculations of design decisions in real buildings.

All calculations for products without shading layers are identical to those from WINDOW 5.2.

WINDOW 6 Research Version includes all of the WINDOW 5 capabilities with the addition of shading algorithms from ISO15099 which are incorporated into the program, as well as an extension of those algorithms with the matrix calculation method.

THERM 6 Research Version includes all of the THERM 5 capabilities with the addition of being able to import and model WINDOW 6 glazing systems with shading devices. Those THERM 6 files with shading devices can them be imported into the WINDOW 6 Frame Library and whole windows with shading devices can then be modeled in WINDOW 6.

1 aMitchell, Robin1 aKohler, Christian1 aKlems, Joseph, H.1 aRubin, Michael, D.1 aArasteh, Dariush, K.1 aHuizenga, Charlie1 aYu, Tiefeng1 aCurcija, Dragan, C. uhttps://buildings.lbl.gov/publications/window-62therm-62-research-version01554nas a2200157 4500008004100000050001500041245001800056210001800074300001200092490000700104520116200111100002301273700002301296700002001319856005701339 1997 eng d aLBNL-3991100aWindow Optics0 aWindow Optics a149-1610 v623 aOptical and radiative properties of glazing materials are primary inputs for determination of energy performance in buildings. This paper revisits the problem and reformulates the calculations to encompass a variety of solutions to practical problems in window optics. Properties of composite systems such as flexible films applied to rigid glazing and laminated glazing can be predicted from measurements on isolated components in air or other gases. Properties of a series of structures can be generated from those of a base structure. For example, the measured properties of a coated or uncoated substrate can be extended to a range of available substrate thicknesses without the need to measure each thickness. Similarly, a coating type could be transferred by calculation to any other substrate. A simple monolithic model for extrapolating from normal properties to oblique properties is shown to have sufficient accuracy for the purpose of annual energy performance calculations. A process is initiated to develop a reliable method for determination of effective indices suitable for more detailed spectral and directional optical calculations.

1 aRubin, Michael, D.1 avon Rottkay, Klaus1 aPowles, Rebecca uhttps://buildings.lbl.gov/publications/window-optics01038nas a2200157 4500008004100000050001400041245005600055210005400111520051900165100002900684700002500713700002200738700002300760700001800783856007900801 1993 eng d aLBL-3394300aWindow 4.0: Documentation of Calculation Procedures0 aWindow 40 Documentation of Calculation Procedures3 aWINDOW 4.0 is a publicly available IBM PC compatible computer program developed by the Building Technologies Group at the Lawrence Berkeley Laboratory for calculating the thermal and optical properties necessary for heat transfer analyses of fenestration products. This report explains the calculation methods used in WINDOW 4.0 and is meant as a tool for those interested in understanding the procedures contained in WINDOW 4.0. All the calculations are discussed in the International System of units (SI).

1 aFinlayson, Elizabeth, U.1 aArasteh, Dariush, K.1 aHuizenga, Charlie1 aRubin, Michael, D.1 aReilly, Susan uhttps://buildings.lbl.gov/publications/window-40-documentation-calculation