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