Transitioning to a Greener Future: Victoria's Shift to the 7-Star Minimum NATHERS Rating for Buildings Explained
In recent years, there has been a growing emphasis on sustainability and energy efficiency in building construction. As a result, many countries have started to implement stricter standards for new buildings, to reduce their environmental impact and maximize energy efficiency. In Australia, Victoria is leading the way by transitioning to the new 7-star minimum NatHERS rating for all.
This progressive move is cause for celebration, as advanced standards will ensure that today's homes are more habitable and economically efficient in the future. In Australia, residences contribute to 7.9% of total energy consumption, 29% of electricity usage, and 11% of greenhouse gas emissions. Improving energy efficiency can reduce household expenses and emissions while providing better protection against extreme climate events. Enhancing new homes' performance is crucial for comfortable, cost-effective, and climate-resilient shelter. With mandatory energy efficiency changes approaching, now is the perfect time to discuss planning a 7-star (or higher) home with your design team and builder.
Understanding the Shift: The Evolution of Victoria's Building Standards
The upcoming changes to Victoria's building requirements signify a leap towards greater energy efficiency. Under the updated regulations, the minimum energy efficiency rating for a new home’s building envelope now stands firm at 7 stars via the Nationwide House Energy Rating Scheme (NatHERS), out of a possible 10. This rating evaluates the energy required to maintain a comfortable indoor temperature, taking into consideration the variations in climatic conditions across different locations. The increased rating translates to a reduction in energy consumption for heating and cooling by approximately 20 to 25 percent in most areas.
The National Construction Code (NCC) revisions are not confined to thermal efficiency alone but also incorporate a novel 'Whole of Home' strategy. Alongside the obligatory 7-star rating for thermal efficiency, a fresh 'energy budget' will be implemented. This budget will consider the usage of energy-efficient appliances and solar energy, setting a cap on the annual energy use for heating, cooling, lighting, and water heating. Where applicable, energy use from swimming pool and spa pumps will also be included. The introduction of solar PV to the home would contribute to offsetting this budget.
A comprehensive Whole of Home assessment will enable homeowners to estimate whether their home can achieve Net Zero Carbon, which means the energy produced over a year equals (or even surpasses) the energy consumed. This remarkable milestone is certainly an objective worth striving for in the quest for sustainable living.
Will the Transition to a 7-Star Design Escalate Costs? An Insightful Perspective
The transition to a 7-star rating might lead you to question the impending cost implications. Interestingly, in many scenarios, the additional cost might not be as substantial as one may assume. The key lies in harnessing passive solar principles, a crucial element in the construction of a 7-star home. As the energy performance prerequisites for new houses escalate, the optimal orientation of your home becomes even more significant. The strategic placement of living spaces towards the north, coupled with adequate shading from the summer sun, remains the most cost-effective solution to enhance the star rating.
Architects and designers are well-versed in the importance of considering the home's orientation and local climatic conditions when designing an energy-efficient home. Shannon Battisson, the National President of the Australian Institute of Architects, emphasizes the need for homes to be designed and built with their specific climate zone in mind. “Ensuring the new 7-star minimum isn't a daunting task, even in the most severe climates, provided we prioritize getting the design aspects right from the onset. If you're planning to build a home, assemble the right team to assist you in orchestrating the design and construction of what will eventually stand as a built legacy for future generations,” says Battisson.
A competent design will vary from one house to another, hinging on various factors like climate, orientation, and construction materials. Nevertheless, in most instances, the new standard can be met through straightforward and cost-effective changes enacted early in the design process. The primary distinctions between a 6-star and 7-star home may involve leveraging opportunities for passive heating in winter and effective shading in summer. Along with good orientation for solar gains, this can be achieved by improving ceiling, wall, or underfloor insulation according to local climatic conditions, and using high-performing glazing to insulate the home against heat loss in winter and heat gain in summer. Homes with sub-optimal orientation will require a more determined effort to reach the 7-star benchmark through enhanced insulation, superior glazing, careful window sizing, and more intelligent floor plans.
Surpassing the 7-Star Threshold
Forward-thinking market innovators and knowledgeable homeowners are already setting their sights on homes rated 8-stars and beyond. With the 7-star rating becoming the new benchmark, achieving ratings higher than the minimum will increasingly evolve into a more manageable and cost-efficient feat. These new regulations mark a significant stride towards homes with superior performance, aligned with the national Trajectory for Low Energy Buildings’ goal of homes that are “zero energy and carbon ready.” In simpler terms, the target is to reach Net Zero Carbon or even True Zero Carbon, offsetting not just operational energy but also embodied energy.
The vision also encompasses future-proofing homes to accommodate electric vehicles by integrating electrical wiring to the garage or carport for a future EV charger installation. As we progress towards buildings with heightened efficiency and improved sealing, it is crucial to address the matter of ventilation to maintain a fresh internal air environment. This can be achieved through design strategies that facilitate natural cross and stack ventilation, allowing for the strategic opening and closing of windows throughout the day. Alternatively, a mechanical ventilation system with heat recovery can be installed for enhanced efficiency— a critical component for exceptionally airtight homes with less than five air changes per hour at 50 pascals (ACH50). While the NCC demands new homes to be under 10 ACH50, post-construction airtightness tests are yet to be made mandatory.
The Impactful Transition from 6-Star to 7-Star Homes: A Step Towards a Sustainable Future
The implementation of the 7-star minimum energy rating has received nationwide approval from the coalition of state and territory building ministers. However, the responsibility now lies with each jurisdiction to devise its own procedure for enforcing these modifications. The NCC 2022 will officially commence on 1 May 2023, with a transitional period extending to 1 October 2023, specifically for the Modern Homes provisions related to energy efficiency, condensation mitigation, and accessible housing. However, some states and territories have suggested postponing its application beyond this timeline. To ascertain how and when these alterations will impact your project, it is advised to consult your local state or territory building authority.
Transitioning from the former 6-star standard to the more stringent 7-star homes, coupled with the implementation of a Whole of Home energy budget, is not merely a change in policy; it's an investment in our collective future. This shift is poised to ensure that the houses we build today, and the ones that will grace our landscapes in the coming years, will stand more resilient against extreme climatic conditions and promise lower operational costs.
The enhancements towards the energy efficiency of new homes, deemed as merely minute alterations by some, will actually ripple through the sands of time, leaving a lasting impact for generations yet unborn. These small yet powerful steps will gradually lead us to the era of homes that are truly net-zero in terms of carbon emissions.
A home that's net-zero doesn't just speak about energy conservation; it signifies the epitome of sustainable living, fostering a harmonious balance with nature. The transformation beckons a lowering of our overall carbon footprint, thereby gently alleviating the pressure we've been exerting on our precious planet.
Being aware of our responsibility towards the environment, and making conscious choices to reduce the impact, is the least we owe to our home, Earth. The shift to a 7-star minimum represents a significant stride towards that direction, acting as a beacon guiding us to a more sustainable and eco-friendly future. It's a bold but necessary move, carving out a path towards a cleaner, greener and more sustainable tomorrow.
