Spot the difference
David Arnott provides a guide to the energy efficiency requirements across the eastern seaboard and their variations
A little over 10 years ago the first requirements addressing energy efficiency were established in the Building Code of Australia. Since their introduction, these provisions have been consistently evolving with a certain inevitability that is associated with any new discipline and could be described as being in an adolescent phase, having not yet reached full maturity.
With that being said, the regulatory requirement for an individual dwelling to perform at a minimum six stars and a building to be Section J compliant has been around long enough for people to know these form part of the approval process. More often than not however, this is only part of the story, and at times, some or all of these requirements aren’t requirements at all. Such is the variation that occurs between each state: when you start to look closely, it can be more difficult to identify the similarities than the differences.
It is all too easy to become comfortable and sometimes even complacent with things that are familiar to us. So in this context there can be a danger of getting into trouble by not fully understanding the different regulatory requirements when designing or constructing in a new location.
In this article I will break down and articulate where some of these variations occur and what the implications are. By doing so, it is hoped by the end you will be able to navigate your way through any unfamiliar territory to a fully compliant building.
What you probably already know
There are two volumes of the now titled National Construction Code (NCC) that have energy efficiency requirements. Volume One deals with building classes 2 – 9 and Section J located there within details the energy efficiency requirements for these classes. Volume Two specifies the requirements for building classes 1 and 10, which can be found in sections 2.6 and 3.12 respectively.
To achieve compliance in either NCC volumes, the method is the same: you must satisfy the prescribed Performance Requirements and these requirements can only be satisfied by a Deemed-to-Satisfy (DtS) Solution, a Performance Solution (such as a NatHERS thermal comfort simulation or JV3 verification method) or a combination of the two. Finally, there can be state and territory variations to any specific provision and it is important to understand when a variation will impact your proposal.
Each volume has an appendices with all state and territory variations listed and Volume Two also has these variations listed throughout the text. This is the foundation of the compliance process, something that in part most readers will be familiar with, but there can be more to it.
What you may not know
Depending on which state or territory the proposal is located, it is not always a prerequisite for an accredited assessor to complete a thermal comfort rating. While a non-accredited assessor may be as competent (or even more competent) than their accredited colleagues, there are simply far fewer cheques and balances that apply to them. There are no auditing or CPD requirements that apply to such assessors and in a dynamic legislative environment, this can put them at a serious disadvantage.
Three neighbouring states, which are worlds apart
Explaining the differences that exist between Queensland, New South Wales and Victoria provides a good opportunity to highlight the magnitude of change that can exist from state to state. It also means that we can more closely examine a few of the key regulatory requirements that exist above and beyond the NCC provisions of those states.
Queensland and the Queensland Development Code (QDC) MP4.1 & MP4.2
To begin with, let’s take a look at compliance for a unit building (Class 2) in Queensland. As it is a Class 2 building it will need to comply with Section J of NCC Volume One and at the very beginning of the chapter, under the heading, we can see the wording “Qld Section J” which indicates a state variation exists.
This variation states that in Queensland Section J must be replaced with Section J of 2009. One of the key differences in this variation is the minimum star rating for sole-occupancy units (SOUs), whereby in 2009 collective SOUs needed to achieve a minimum average energy rating of four stars, and individually achieve a minimum of either three or three and a half stars (depending on the climate zone in which the proposal was located).
What is not explained in the NCC though is that these requirements are superseded by the Queensland Development Code (QDC) and specifically MP4.1 whereby the requirements are higher than Section J in BCA 2009, although the method of assessment (NatHERS) remains the same. Therefore the actual performance requirements for a SOU in Queensland are as follows:
“Collectively achieve an average energy rating of not less than 5 stars; and individually achieve an energy rating of not less than 4 stars.”
QDC MP4.1 should be read carefully when completing any kind of residential development in Queensland as it covers more than just the above and has further requirements that surpass the NCC around items such as hot water, lighting and water conservation. Additionally QDC MP4.2 should be consulted to ensure your proposal meets any obligations that might exist regarding rainwater tanks and other supplementary water supply systems.
New South Wales and the Building Sustainability Index (BASIX)
Residential development in NSW is subject to the Building Sustainability Index (BASIX). Implemented in 2004, BASIX is an online assessment tool that is used to assess all new and altered Class 1, 2 and part 4 buildings with the aim of reducing the water and energy consumption. The DA application of any residential proposal needs to be accompanied by a BASIX certificate which outlines how the proposal will achieve its water and energy savings. Running successfully for over 10 years now, BASIX aims to give a more holistic view of residential sustainability by considering more than just the thermal comfort of proposed dwellings.
There are three sections of a BASIX assessment: water, thermal comfort and energy. The water and energy sections have minimum scores that need to be reached, this is shown as a percentage and is based on saving ‘x’ per cent more water or energy when compared to pre-2004 usage. There are several options for compliance in the thermal comfort section, depending on what type of development you are assessing. For single dwellings there is the choice between two Do It Yourself (DIY) options, which is similar to Section J DtS, or a simulation method. In a multi dwelling assessment the simulation method is mandatory.
BASIX thermal comfort simulations have some clear differences from their NatHERS cousins; most notable of them is that a BASIX thermal comfort simulation is not required to reach six stars. Instead, BASIX gives individual heating and cooling caps based on the climate zone. With this criteria a dwelling may be able to achieve a pass in BASIX with a three and half star rating, the argument being that the additional savings in water and energy help to offset the discrepancy with other state requirements.
The practical implication to this point is dwellings in NSW often have a reduced specification when it comes to things such as insulation and glazing, and therefore the requirements for an interstate home (outside NSW in this example) can come as a bit of a shock to someone used to working in BASIX.
Finally, assessors also need to be mindful that there are a different set of protocols that apply to NSW assessments. For the most part, the rules are the same but there are a few key differences, and if these are overlooked it can have an impact on the outcome, not to mention leave you liable down the track.
Victoria and the Built Environment Sustainability Scorecard (BESS)
BESS is the newest kid on the block and has been introduced to replace the existing Victorian incentives: STEPS and SDS. To associate BESS with all of Victoria is not 100% accurate because while BESS is a Victorian incentive, it is not applicable to the entire state but rather \a requirement of specific local government areas (LGA) situated in and around Melbourne. In the future there is potential for BESS to be applicable Australia-wide, in any local government area that chooses to subscribe to it. Yet for now it is only applicable in approximately 15 LGAs.
Similar to BASIX, BESS is an online tool and was developed by the Council Alliance for a Sustainable Built Environment (CASBE) and aims to ‘provide flexibility for the user while delivering sustainability outcomes’. Unlike BASIX, BESS can be used to assess both residential and non-residential developments, where the questions asked are dependent on the type of proposal you are assessing and in each instance the user has multiple options to demonstrate compliance.
BESS is a comprehensive approach, which covers: management, energy, water, stormwater, indoor environment quality (IEQ), transport, waste, urban ecology and innovation. An overall score is given depending on how well the proposal performs in each of these areas.
BESS differs from BASIX and QDC MP4.1 in the sense that it does not replace or overwrite the building code requirements, rather the measures are additional items aimed at improving a proposals performance beyond the minimum national standards. By doing so it works much in the same way as Green Star, however when BESS is applicable it is mandatory.
Due diligence, check beyond the NCC
As you can see, from the above examples, there are many differences that occur between each state and territory and this is before we even scratch the surface of additional local government area obligations. Obviously there are far too many variations for us to go through all of them, but the key message is to make sure you and your assessor understand that compliance with the NCC is often just the first step.
Real care must be taken to ensure all applicable conditions are met and this is particularly true when you are building in an area that you are not familiar with. In these instances it can be advantageous to speak with someone local. Initially a little bit of extra reconnaissance might be required, but this time is seldom wasted.