The National Construction Code (NCC), the minimum construction standards that all Australian buildings must abide by, is having an update! The newest addition was released in February 2019 and will be implemented by all States and Territories on the 1st of May 2019. Importantly, NCC 2016, can be used to demonstrate compliance until the 1st of May 2020. So, dependant on your building surveyor agreeing, there is some breathing space.
Biggest Changes for Energy Efficiency?
RIP to the VURB.
A method used to surpass the 6 star legislation was to utilise the “verification using a reference building” (VURB) clause of the NCC. In simple terms, we would create a second model of the home using the minimum NCC standards, and if the original home design surpassed the reference model in cooling and heating loads it would get the tick of approval. This typically worked for buildings that were achieving 4-5 stars.
However, the proposed NCC changes have altered our reference model. Instead of using minimum acceptable practice, the reference has to be modelled with specifically designed construction, e.g. the roof must be made of a particular material, at a specific pitch and solar absorptance and insulation matching the climate zone of the home. To put this in perspective, in the past we would have simply changed the insulation to the appropriate climate zone and left the rest of the roof the same. Now the entire roof structure changes, which in turn changes the ventilation, the amount of heat coming in through the roof and the insulation. The reference model’s construction applies to the entire buildings construction, glazing and ventilation.
Basically, we’re making a whole new house. And it has a great energy rating.
Real Life Impact
We teamed up with other industry leaders to assess the impact of these VURB changes, and what would have been the results on some real, previous assessments that had passed the current VURB method. Close to 150 houses were rated in climate zones 13, 47, 52, 54 and 58, five of the most populated climate zones in Western Australia. A variety of residential buildings were modelled, and accounted for different floor and wall types, the number of storeys in the house and insulation. Of these models, only 18 passed the updated verification method with no changes. Interestingly, a disproportionate number of houses that complied were brick veneer. It’s important to note that this does not imply that brick veneer houses will always rate better than their framed or cavity brick counterpart, but because the new verification model is brick veneer. In these cases, the real house and model house are the most similar in construction and therefor the gap between the two is lower. On the other hand, there seemed to be no favouritism for a particular climate zone. This study also looked at what changes would be required to achieve the target rating. On average, the homes required 6.2 stars to surpass the cooling and heating loads of the reference model, achieving a 6 star home anyway.
Can I still use a VURB?
VURB assessments performed by Sustainability WA are still compliant with the current version of the BCA, Building Commission guidelines, press releases from CSIRO, and can still be used, in most cases, for building license applications up to May 1st 2020.
What’s our advice?
If you’re building a new home, don’t rely on the VURB to get you through. Design your house with passive heating and cooling in mind, and we recommend involving your energy assessor early in the design process. It is always cheaper (and less frustrating) to design a good home than it is to do last minute changes to a design that you love.
If you’re renovating a home, the alterations and additions protocol still apply - your star rating to comply is dependent on how much of the house is being altered.
And if you’re still worried, remember that we have until May 2020 before we have to start enforcing the new rules. Phew!