Set up the compliance mindset: envelope, fenestration, nett floor area, U-value and SHGC.
By the end of this lesson you should be able to decide what must be included in a fenestration check and what information you need before calculating.
Fenestration compliance starts by identifying the parts of the building that separate conditioned interior space from the outside. Windows, glazed doors and roof lights are assessed when they form part of that envelope. Garages, storerooms and similar excluded spaces should only be ignored where the separating construction is itself treated as the envelope.
The performance value used for a window or glazed door should represent the whole fenestration element, not only the centre pane of glass. Frames, spacers and opening type can change the total U-value and SHGC, so supplier data should be checked carefully before entry.
U-value describes heat transfer through the element. Lower values usually mean better insulation. SHGC describes how much solar heat passes through the fenestration. Lower values usually reduce unwanted solar gain, especially on sun-exposed elevations.
Create one row per window or door type and keep supplier U-value and SHGC evidence with the project record.
A single storey has 52 m2 nett floor area and three glazed elements: 1.8 m2 at U 2.8 / SHGC 0.32, 5.0 m2 at U 2.2 / SHGC 0.25, and 1.1 m2 at U 3.0 / SHGC 0.35.
Enter each glazed element with its area, orientation, U-value and SHGC. Use the result cards to check glazing percentage and weighted performance.
The important decision is not only whether the numbers pass, but whether every value can be traced to drawings and supplier data.
Are roof lights separated from vertical fenestration?
List every external window, glazed door and roof light on one storey.
Flag the missing evidence, use a conservative assumption where appropriate, and avoid claiming compliance until the information is confirmed.
Fencalc XA2021