This tool calculates heat loss for the calculation method of NZS 4218:2009. It is not a replacement for NZS 4218:2009, and designers are advised to obtain a copy from Standards New Zealand.
What to do:
About the NZS 4218:2009 Calculation Method Tool
Instructions for using the NZS 4218:2009 Calculation Method Tool
About the NZS 4218:2009 Calculation Method Tool
What this calculation tool does
Designers need to select the climate zone and wall construction type(s) and accurately enter all area and construction R-values for the various building elements. The tool then applies the calculation method automatically, and pass/fail compliance is determined where possible.
Compliance with NZBC clause H1
Only the following designs are eligible to use this tool to demonstrate compliance with NZBC clause H1:
This tool is NOT the calculation method of NZS 4243 and MUST NOT BE USED for this purpose.
Refer to New Zealand Building Code clause H1 Energy efficiency 4th Edition for full details.
Measurement of areas
Refer to NZS 4218:2009 for definitions of element areas and how to measure them.
Construction R-values
Designers must input construction R-values for the roof, walls and floor. This is NOT the same as the insulation R-value. Refer to NZS 4218:2009 for the definition of construction R-values.
The BRANZ House Insulation Guide Preview/Buy gives construction R-values for the most common construction types used in residential construction in New Zealand and can be used with NZS 4218:2009.
Glazing construction R-values must be taken from Appendix C of NZS 4218:2009.
Interpretation of NZS 4218:2009
This tool is implemented according to an interpretation of NZS 4218:2009.
Limitations and liability
BRANZ Ltd accepts no liability for loss or damages resulting from use of this tool. The accuracy of the calculation relies on the designer entering accurate and truthful values.
Restrictions on use
This tool is only to be used in its full unmodified form.
More information on NZS 4218:2009 and NZBC clause H1
How to use the BRANZ NZS 4218:2009 Calculation Method Tool
Open/print a PDF of these instructions
IMPORTANT: Only enter data or select options in unshaded cells. Select options from a drop-down list in cells shaded light blue.
A. Set up the climate and building construction type:
B. Enter the areas and construction R-values for all building elements:
C. Check the Project Summary:
D. Save a copy of the spreadsheet for your design documentation - change the file name as appropriate.
E. Print a copy of the spreadsheet for your consent documentation. Supply all printed sheets with the consent so everything can be checked and include any relevant supplementary information.