ALF help

Design help

On the Design pages you enter information about the particular house design and location to perform an ALF analysis on it.

Window Construction Popup

Window Construction Popup

The 'WindowConstruction.txt' file contains the thermal and optical properties of the glass and frame types, which you can select on the Windows page. It contains data for the most common glass and frame types of New Zealand window, including data on how the thermal properties change when curtains are drawn during the night.

The first data row contains the full description of the available frame types. These are shown in the 'Tooltip's when you hover the mouse over the drop-down list on the Windows page.

The second data row contains the abbreviated frame descriptions. They are shown in the 'Frame Type' drop down list on the Windows page.

The first column contains the full description of the glass types, which you can select from the 'Glass Type' drop-down list on the Windows page. The full description is shown in the Tooltips of the 'Glass Type' drop-down list.

The second column contains the abbreviation of the glass type. The abbreviations are shown in the 'Glass Type' drop down list.

The following columns shows the window SHGC and the R-value separated by a '|' for the frame which is indicated at the top of the column. The insulation value of windows is generally described in terms of 'U-values'. The R-value is defined as the inverse of the U-value. The R-values of an unlisted window type can therefore be calculated as R=1/U.

The SHGCs and the R-values in the file are calculated for a typical window with an overall size 1500x1800 comprising of an awning sash next to a fixed pane using the ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) conditions.

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Contact us at Branz for further information about the ALF 3.2: Annual Loss Factor.