The fields within the window screen must be populated by the User.

Window Label: Use this field to assign an identifying label to the window (e.g. "Bay window", "Dining room window", etc.). If the wizard was used to create the house, windows will be labelled based on their orientation.

Window Details: Use the Window Details drop down options to select the window code that appropriately describes the window performance. The information provided in the window code will be used to calculate the energy performance factors; thermal resistance (in RSI, which is the inverse of U-factor), solar heat gain coefficent (SHGC) , and Energy Rating (ER, 2009 version). These window energy performance factors, shown at the bottom right of the Window Screen, are specific to the size of the window being modeled.

For simulation projects that require the most accurate representation of window performance, such as for code compliance, or where the window energy performance ratings are known (shown on the window label) the best approach is to develop a User-Defined code using the known window energy performance ratings. For simulation projects in which a coarse representation of window performance is acceptable, the window details can be specified in terms of the construction details (i.e glazing type, coatings, etc.) using the Code Selector.

Additional guidance on Window Codes is provided on the next Page.

Location: Use the window Location field to specify where the window is installed in the house. Windows can only be placed in ceilings, walls, doors and foundation components (i.e. crawl space and basement). A window's location is automatically populated based on the component in which the window was created in or duplicated from.

To move the window to another component, drag and drop the window (the Location field will automatically be updated) or select the desired Location. If the window is located in a particular component (e.g. Wall-1) and the Location field is changed to another component (e.g. Wall-2), then HOT2000 will automatically move the window to the other component (in this case Wall-2) in the tree view.

Shading: Use default values to define the Shutter R-Value and the Curtain shading factor.

Orientation: Specify the direction which the window faces as south, southeast, east, northeast, north, northwest, west, or southwest.

Number: Use the Number field to define the number of windows of the type and size specified for the entry. Identical windows that are attached to the same building component (such as a ceiling, wall, or door) and that have the same orientation, and overhang width and height, glazing, coating, fill type, spacer type, and frame material may be entered in a single window screen by specifying the number of windows in the field. The value in the Number field cannot exceed nine.

Do not group windows that have different overhang widths and heights, windows on different building components, or windows facing different orientations. Do not enter the sum of the window dimensions, rather enter the dimensions of just one window as they all must be identically sized to use the Number field.

Width and Height: Enter the Width and Height of the window (including the frame) in either millimetres or inches.

For situations where measurements are taken from the outer extremities of the glazing, add 76 mm (3 in.) for fixed windows, and 152 mm (6 in.) for operable windows, to the width and height. See Section 3.5.7.1 of the EnerGuide Rating System Technical Procedures for more information. For a glass block window, enter the exact dimensions as measured without adding to the width or height.

Gross Area: The Gross Area field displays the area of the window in square meters or square feet as calculated by HOT2000.

Overhang Width and Header Height: These values are used to calculate the shading effect of overhangs. Enter the Overhang Width as measured from the outside of the glass to the tip of the overhang. If the glass is recessed into the wall as shown below, include the recessed distance. Enter the Header Height as measured from the top of the glass to the underside of the overhang. For an overhang that descends down over the glazing, enter the Header Height as a negative number.

Tilt: Use the Tilt field to specify the window's tilt, such as for a sloped window in a wall or a skylight in a roof. Specify the Tilt as Vertical, Horizontal, Same as roof, or User specified. If User specified is selected, enter the angle in the Value field which ranges from 0º (horizontal) to 90º (vertical). If the Same as roof option is selected, ensure that the window component is located in a ceiling component or an error message will be displayed when a calculation is performed.

Based on the data entered in the Window screen, HOT2000 will calculate the energy rating (ER), RSI value, and Solar Heat Gain Coefficient (SHGC) for each window. As mentioned earlier, these values are specific to the size of the window being modeled.

Size-specific performance values: It is important to make the distinction between the size-specific RSI and SHGC and the window energy performance ratings that are found on NFRC or ENERGY STAR window labels. The labels on a window show the rated values, which are determined for reference sizes specified in the CSA A440.2 test method. Building codes, and voluntary programs typically specify minimum performance using CSA A440.2 rated values, not size-specific values. Therefore it is incorrect to infer from the size-specific values calculated by HOT2000 and shown on the Window Screen, that a window meets or does not meet the rated values specified in a code or program.

CSA A440 Reference fenestration sizes