01540nas a2200133   4500008004100000050001400041245003600055210003400091520113400125100002501259700002901284700002201313856007101335       1994                        eng d  aLBL-3529800aWINDOW 4.1: Program Description0 aWINDOW 41 Program Description3 a<p>WINDOW 4.1 is a publicly available IBM PC compatible computer program developed by the Windows and Daylighting Group at Lawrence Berkeley Laboratory for calculating total window thermal performance indices (i.e. U-values, solar heat gain coefficients, shading coefficients, and visible transmittances). WINDOW 4.1 provides a versatile heat transfer analysis method consistent with the rating procedure developed by the National Fenestration Rating Council (NFRC). The program can be used to design and develop new products, to rate and compare performance characteristics of all types of window products, to assist educators in teaching heat transfer through windows, and to help public officials in developing building energy codes.</p><p>WINDOW 4.1 is an update to WINDOW 4.0. The WINDOW 4 series is a major revision to previous versions of WINDOW. We strongly urge all users to read this manual before using the program. Users who need professional assistance with the WINDOW 4.1 program or other window performance simulation issues are encouraged to contact one or more of the NFRC-accredited Simulation Laboratories.</p>1 aArasteh, Dariush, K.1 aFinlayson, Elizabeth, U.1 aHuizenga, Charlie  uhttps://facades.lbl.gov/publications/window-41-program-description