New Zealand Building Code 2021 Update Consultation

Here's a summary of my main submission points for the current Building Code Update consultation from the Ministry of Business, Innovation and Employment.

Please feel free to copy, share, comment here. But most importantly, make sure you submit by May 28th.

• Approve of moving to six climate zones. This provides a more realistic assessment of the performance requirements for buildings across the country. While more robust methods such as the Passive House Planning Package (PHPP) references 18 climate zones, six is a reasonable approximation for the industry at large. 
• Specifying R-value is the wrong approach. The Building Code is designed to be a performance based code, not a prescriptive set of requirements. Accessible and reliable thermal modelling software is now readily available. Whole dwelling performance outcomes measured in kWh/(m2·a) should be set rather than specific and theoretical thermal properties of individual building elements. 
• The New Zealand Building Code should be aligned with the Building for Climate Change framework proposed by MBIE. In particular, a stepped roadmap should be implemented similar to British Columbia’s Energy Step Code. The Energy Step Code Aotearoa with Primary Energy (ESCAPE) framework could be used for this purpose to achieve the target thermal performance demand of 15 kWh/(m2·a) by 2032.

• The measures proposed in this update should only be seen as an interim progression while a Step Code is implemented. 
• The cost-benefit analysis shown in the consultation document has limited relevance as costs are based on current materials and methods which will surely change as soon as higher standards are implemented. Conversely, the energy savings are largely hypothetical because New Zealand homes are often under heated. Health and productivity savings resulting from healthier homes are likely to be far more substantial and significant than energy efficiency cost savings but have not been accounted for nor estimated.
• Infiltration must be considered. Uncontrolled air movement significantly reduces the effectiveness of insulation and can also lead to accelerated structural degradation and adverse health of occupants. 
• Infiltration of buildings should be measured. Unlike installed R-value which is impractical to measure, building envelope permeability can be reliably and accurately measured. 
• MBIE must resist pushback from the industry regarding the cost of supplying products with improved thermal performance. The issue of housing affordability is about the total cost of ownership. By allowing homes to be built that are not fit for purpose, we are increasing the burden of fuel poverty, excess health costs, productivity losses, and crippling repair bills.

For more on this, see the Home Style Green podcast episode 252.