The cost of heating and cooling a house has risen substantially over the last decade or so, and the decision-making bodies around planning and building in Australia have responded accordingly. We have seen progressive response to make buildings more energy efficient, on both the fronts of how they are designed (in an architectural sense) and how they are assembled (by way of build technology). This is having an impact on the design deliverables and construction costs for people developing and subdividing property in Western Australia.
The NCC and BCA are now referenced by building services departments at all local governments to align with their standards, meaning it is necessary for developers to meet a mandated minimum of a seven-star energy efficiency rating in order to obtain a build permit. Leaving it to build permit stage to work out how you are going to do this though can back you into a corner. A lot can be done at design stage to help as well, by way of things like Solar Passive design.
In context for Western Australia, the good news is that solar passive design is practically enshrined in most volumes of the R-codes of WA now. For Part C “medium density”, it’s not even an option anymore. Care still must be taken though; good design from an energy efficiency perspective can be (and should be) balanced against what build technology options are available to meet the mandated energy efficiency ratings. A hybrid approach usually achieves the most economical results, which is important for property developers in WA.
In the course of our property developments, we are beginning to consider both the design and build technology variables of energy efficiency in tandem, much earlier. We do this at DA stage now, and there a few reasons why. At time of writing, we need to achieve a seven-star energy efficiency rating. In some local government structure plan areas, or by way of local planning scheme areas, we need to achieve one star higher (eight stars). As a result, this aspect of design now needs a more considered and integrated approach, much earlier in design process. To produce an energy efficient dwelling, we need to consider both design aspects (things like orientation of dwelling and size of openings, solar penetration and overshadowing, setback, building height and room volumes, extent or nonexistence of eaves, etc) and the build technology that’s used to put it together ( wall and floor systems and materials, roofing finishes and colours, flooring finish materials , insulation, HVAC, glazing etc).
There is now a real risk of designing something that meets planning controls effectively, but when the wand is waved over the design at build permit stage, lots of insulation, materiality changes (sometimes expensive) and large amounts of upgrades to things like glazing and sun shielding can be required, quickly adding substantial cost to the budget. Consequentially, some coordinated preliminary modelling on energy efficiency that allows us to consider the BP stage impact of DA prerogatives prior to lodging an application for a planning approval is now a clever idea. This allows you to make more effective and cost-conscious decisions that consider both the design aspect and the build technology required to meet the energy efficiency rating. This may end up in window and door openings changing size or being shifted, eaves being reduced or increased, or dwelling height /wall positions moving, but it can save some big dollars for expensive upgrades later when your only option with design and a new DA is spending up on build technology. It is advised going forward that all developers do the same, by way of conducting preliminary energy assessment and modelling at the stage of developing a DA set.
You can learn more about planning approvals processes, good design, design coordination and planning controls like the Rcodes in our online books and courses, here
To discuss building, subdivision and design coordination in Western Australia, and the best ways to develop a property, fill out a contact form here and we can get in touch to discuss.
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