From May 1st 2020, the NCC 2019 regulations will be mandatory for new building designs. Whilst generally the energy efficiency requirements are more stringent under NCC 2019 (giving rise to some design and costing changes), there are some new ways that the code allows for flexibility in meeting these requirements.
In the spirit of ‘always looking on the bright side’, here are a couple of important ways the new code will enable some designs to achieve compliance more easily:
1. Walls/glazing on different orientations can be traded off against each other.
Under the previous code (NCC 2016, DTS), glazing was assessed separately for each orientation. Under NCC 2019, there are now two methods available – one which assesses each orientation separately, and a second method which takes the average of all the building orientations. Both are approved methods in the legislation.
Using method 2 means that if the walls and glazing on one façade underperform a little, this can be offset by other walls which overperform.
So for example, you may be able to make a beautiful east facing window slightly larger by increasing glazing performance on other façades (e.g. by reducing size or adding tinting). Or, you may be able to keep project costs down by not requiring low-e glass on one façade by adding tinting on other façades.
This change provides for a lot more flexibility in coming up with an energy solution for a building using DTS.
2. Wall requirements are reduced for most climate zones/building classes.
Under NCC 2016, walls required a minimum R value of R 2.3 (internal walls) and R 3.3 (external walls) – taking climate zone 2 as an example.
That’s changed, and under NCC 2019, internal and external walls can have a minimum R value as low as R 1.0.
Building classes 3, 9c, or 9a ward areas have their own set of minimum values which are typically closer to the old values. Climate zone 1 also has its own minimum values. But for all other climate zones and building classes, the minimum values are:
- R 1.0, where a wall makes up less than 80% of a façade area (e.g. >20% glazing on the façade).
- R 1.4, where a wall makes up 80% or more than the façade area.
While there are certainly challenges in transitioning to the NCC 2019 requirements, new tools like these will provide designers and energy assessors with more flexibility in designing compliant solutions for their build.
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