Legislation and mandatory insulation requirements

A law introduced that makes it compulsory for house insulation to be fitted to all new residential homes as of November 2011. The law is because of Eskom’s Demand Side Management (DSM) Plan. Eskom is desperately trying to supply enough electricity to South Africa with limited power sources. The power utility has realized that increasing the supply of electricity (building new power stations) will ultimately take years. Eskom is therefore trying to address the imbalance between supply and demand from the demand side.


An estimated 3500 MW in electricity could be saved by 2020 if thermal house insulation and high-performance window systems were introduced today into all new residential and commercial buildings. This is incidentally almost twice the electricity currently produced by our only nuclear power plant, Koeberg (1800 MW).


By fitting home insulation, South Africans can take it on themselves to help prevent the inconvenience of load shedding. However, installing home insulation and complying with SANS 10400-XA needn’t be seen as a grudge purchase. In fact, you get long-term financial savings and a comfortable living space whilst adding to the resale value of your property after the installation of house insulation.

SANS 10400–XA: Energy usage in buildings

Insulation Climatic Zones

gallery/climate zones south africa

The home insulation requirements for SANS 10400-XA are dependent on the climatic zones of South Africa. The thickness of the house insulation required is determined according to which zone your building is located. Below is a map illustrating these different zones.

Zone 1

- Cold interior

Zone 2

- temperate interior

How thickness required is calculated

Total R-Value required - 3.7

Total R-Value required - 3.2

For our example, we will use a typical tile pitch roof structure or home in zone 2.


Total R-Value require for zone 2

  • 3.2

Average R-Value of roof tile, air space and ceiling

  • 0.35

R-Value of insulation required (Total R-Value - R-Value of roof common structure)

  • 3.2 - 0.35 = 2.85

Thickness required to achieve specified R-Value (R-Value of insulation required x Thermal conductivity of Thermguard)

  • 2.85 x 0.040 = 115mm


Different roof construction will either require thicker or thinner insulation. This will depend on various factors that we can assist with. Do not believe the common myth propagated by untrustworthy contractors that thicker insulation is always better. Your roof structure might only require 75mm of insulation thus saving you money where it would be unnecessary to install 135mm.


Whilst every effort is made to make sure we install the correct thickness required for your area and your needs, get in contact with us so we can assist you with your requirements.