The following requirements with regards to fenestration are applicable in accordance with SANS 10400-XA Energy usage in buildings:

1. Buildings with up to 15 % fenestration area to nett floor area per storey comply with the minimum energy performance requirements.

2. Buildings with a fenestration area to nett floor area per storey that exceeds 15 % shall comply with the requirements for fenestration in accordance with SANS 204.

3. All fenestration air infiltration shall be in accordance with SANS 613.

Importance of SHGC and U Value
SHGC (Solar Heat Gain Coefficient) and U-Value are critical considerations when specifying windows and glass.