The Window properties tool is used to determine the effective window properties (i.e. area, U-value and solar heat gain coefficient) and individual window costs. This tool is useful when windows of different sizes and/or different properties are installed on the same face of the building. Frame effects can also be accounted for to adjust U-values and solar heat gain coefficients from rated values when windows differ from the rated size. The user can consult the RETScreen Product Database for more information.

The window property calculation is performed in a separate worksheet named "Window," which can be accessed by clicking on the blue hyperlink ("Click here to access form") or on the "Window" worksheet tab that appears at the bottom if this tool is selected. The user enters the appropriate data in the Window worksheet.

This tool is a more detailed companion tool for the Building envelope form for Energy efficiency measures projects. After completing the input cells below the user should return to the Building envelope form to enter the major items summarised at the bottom of this tool.

Note: RETScreen users might recognise this tool from the separate RETScreen Passive Solar Heating Project Model (PSH3). The Building envelope form, along with this more detailed Window properties tool, allows the user to prepare a more comprehensive analysis of passive solar heating and/or cooling projects.