NZS 4218 calculation method and permitted glass areas: Version variances

When using the calculation method from NZS 4218:2009 as a means of compliance for H1 Energy efficiency, check which version of the standard is being referenced. The maximum glass area depends on the version being used:

  • NZS 4218:2004 Energy efficiency – Small building envelope, which is the version cited in H1/AS1, gives the maximum glass area as 50% of wall area.
  • NZS 4218:2009 Thermal insulation – Housing and small buildings, which we recommend using to support an alternative method for H1 compliance, gives the maximum glass area as 40% of wall area.

From BRANZ Guideline, December 2016

Buy NZS 4218:2004

Buy NZS 4218:2009

Published in building.