Part XA of the National Building Regulations covers energy use. It applies to new buildings and extensions that need plans, and the plans have to show how they comply. The standard behind it, SANS 10400-XA, was first published in 2011. Edition 2 was published in November 2021 and replaces it.
What it asks of a house
- Hot water. At least 50% of the yearly hot water heating must come from something other than an electric element: a solar water heater, a heat pump, heat recovery or gas. Hot water pipes must be insulated.
- Roof insulation. Roofs need a minimum insulation value, which depends on the climate zone. Metal roofs need a thermal break.
- Walls. In the 2011 edition, standard masonry cavity walls are deemed to comply; other wall types need a minimum insulation value.
- Windows. In the 2011 edition, up to a set glazing area per floor the prescriptive rules are enough; above it the glazing has to be calculated (the "fenestration calculation" councils ask for). The 2021 edition changed how windows and shading are calculated.
Two ways to comply
The prescriptive route follows the rules for orientation, shading, walls, windows, roof and hot water. The performance route is a rational design by a competent person showing the building uses no more energy than allowed. For an ordinary house, the prescriptive route is normal and the registered professional declares it on the submission.
The 2021 edition is sold by SABS, so the figures on your plans come from the current standard, not from this page.
Questions people ask
Does an extension need to meet SANS 10400-XA?
Yes, the new part does. Councils ask for the energy information, often the fenestration calculation, on additions as well as new houses.
Sources
Checked October 2026. Councils change their tariffs every July, so confirm fees before you pay.