BASIX requires the following details about the windows and glazed doors in the dwelling:
- orientation
- glazing size (including frame) – height and width in millimetres (mm)
- operating type
- frame and glass type
- shading
- overshadowing
When you enter the Windows tab for the first time, you will be asked to enter the number of windows for each orientation sector. You can subsequently add windows in each orientation sector from the Windows tab.
Include windows and glazed doors in bathrooms. Do not include windows and glazed doors in unconditioned garages.
The DIY method allows up to 40 different windows to be entered. Combining windows of the same type and orientation is not allowed. The Simulation method should be used if the dwelling contains more than 40 windows.
You can also remove selected windows from the Windows tab. You will be prompted to confirm if the selected windows are to be removed.
The table in the Windows tab shows all windows and glazed doors grouped by orientation. BASIX allows you to enter a window or door number for each element. It is recommended that you give them the corresponding window or door numbers as they are shown on your plans to assist certification at a later stage.
Operating type, frame and glass type, shading and overshadowing details can be entered by selecting the window(s) or glazed door(s), then clicking the button at the relevant column heading.
After you have selected the operating type, frame material and glass type of a window or glazed door, BASIX will assign the corresponding U-value and Solar Heat Gain Coefficient (SHGC) and display them in the table.
U-Value and SHGC
- U‑Value refers to the Total Product U-Value, which is a measure of the ability of the window (glass and frame together) to conduct heat. A lower U‑Value indicates a better insulator. Heat will flow inward when it is hotter outside (cooled house in summer) and flow outward when it is hotter inside (heated house in winter).
- SHGC refers to the Total Product Solar Heat Gain Coefficient, which is a measure of how readily glazing (glass and frame together) transmits radiant solar energy. It is the fraction of the incident solar radiation that is admitted through the glazing, including both the amount directly transmitted and the amount absorbed and subsequently re-radiated inwards. A lower SHGC indicates that less of the solar energy falling on the glazing is admitted.
The U‑Value and SHGC are evaluated according to the Australian Fenestration Rating Council (AFRC) guidelines, which are based on the National Fenestration Rating Council (NFRC) procedures in the United States of America.
BASIX will provide you with feedback on the glazing design if your project does not pass Thermal comfort. To pass Thermal comfort, you will need to improve your glazing design.
Note: Glazing feedback are shared between the windows, glazed doors and skylights.
Certifying the windows and glazed doors in your dwelling
For the following glass and frame types, you are not required to provide certification of the U-value and SHGC of the windows installed in your dwelling:
- aluminium frame with single glazed clear glass
- aluminium frame with double glazed (air-filled) clear glass
- timber/uPVC/fibreglass frame with single glazed clear glass
- timber/uPVC/fibreglass frame with double glazed (air-filled) clear glass.
Descriptions of the BASIX certificate for the above glass and frame types must match the windows installed in your dwelling.
For all other frame and glass types, the BASIX certificate will state the maximum allowable U-Value and the acceptable SHGC range. For these frame and glass types, documentation must be provided to the certifying authority that the U-Value and SHGC are within the acceptable range; it is not mandatory to match the description.