WINDOW Documentation

WINDOW Documentation

User Manuals

The latest documentation for WINDOW 7. If you find any errors or areas which you feel need more explanation, please post that on the WINDOW Forum page.


  • Create a Glazing System (QuickTime Movie)
  • Creating a Window with a Generic Frame (QuickTime Movie)
  • Complex Glazing Summary (PDF)
    • Presented at the Spring 2008 NFRC Meeting, Nashville, TN

Technical Documentation

Comprehensive documentation of calculation procedures in WINDOW

WINDOW program implements the ISO 15099 algorithms and includes additional functionalities not included in ISO 15099, such as:

  • Additional shading devices. The full list of shading devices included in WINDOW 7.6:
    • Horizontal louvered blinds, aka Venetian blinds
    • Vertical Louvered blinds
    • Cellular shades, aka Honeycomb shades
    • Pleated shades
    • Roller shades
    • Solar screens
    • Woven shades (idealized "fabric" consisting of regularity-spaced threads - something like insect screen or very regularly woven fabric)
    • Fritted glazing
    • Diffusing Glazing
  • Glazing deflection
  • Vacuum glazing
  • Chromogenic glazing
    • Electrochromic glazing
    • Thermochromic glazing
  • Radiance-based rendering of an illumination of a typical building space
  • Advanced display of results, including carpet plots of Transmittance, Reflectance and SHGC for entire year

ISO 15099 standard "Thermal performance of windows, doors and shading devices - Detailed calculations." can be obtained from:

Additional Documentation

The following reports and papers describe these additional capabilities and/or elaborate on ISO15099.

  • Bidirectional Optical Properties of Slat Shading: Comparison Between Raytracing and Radiosity Methods (PDF)
    • (Submitted to Solar Energy but not yet published)
  • Documentation for LBNL BSDF XML Format
    • Found in Section 6.4 of the WINDOW 6.1 / THERM 6.1 Research Version User Manual (PDF)
  • WINDOW BTDF Output File Documentation
    • Found in Section 6.3 of the WINDOW 6.1 / THERM 6.1 Research Version User Manual (PDF)
  • Verification Results
    • WINDOW 6 Verification Results (PDF)
    • June 12, 2006
  • Joe Klems Matrix Method Publications
    • A New Method for Predicting the Solar Heat Gain of Complex Fenestration Systems. I. Overview and Derivation of the Matrix Layer Calculation 1993 (PDF)
    • A New Method for Predicting the Solar Heat Gain of Complex Fenestration Systems. II. Detailed Description of the Matrix Layer Calculation 1993 (PDF)
    • NFRC WINDOW 6 / THERM 6 Training for Specular Systems (Power Point Presentation, Oct/Nov 2010) (PDF)
  • Comparison of WINDOW 5 / THERM 5 and WINDOW 6 / THERM 6 Results for Specular Glazing Systems (PDF)
  • Experimental validation and model development for thermal transmittances of porous window screens and horizontal louvred blind systems
    • This paper outlines a review and validation of the ISO 15099 centre-of-glass thermal transmittance correlations for naturally ventilated cavities through measurement and detailed simulations. The focus is on the impacts of room-side ventilated cavities, such as those found with solar screens and horizontal louvred blinds.
  • Modeling Thermal Performance of VIG: WINDOW and THERM Software Tools