News
7 stars and Whole of home coming May 1st 2024 for Vic
Did you know that from 1st May this year, the state of Victoria will transition to the new National Construction Code (NCC) 2022 energy provisions including the move from the minimum 6 to 7 stars? And for the first time, the Whole of Home calculation will be introduced.
This is great news, as the improved standards will ensure that the homes built today will be more comfortable to live in and cost less to run now and into the future.
In Australia, our homes are responsible for 7.9 per cent of all energy use, 29 per cent of all electricity use and 11 per cent of all greenhouse gas emissions. Making them more energy efficient can cut household energy bills and emissions, as well as provide better protection from extreme climate events like heatwaves. Homes are long-lived assets, and retrofitting later to improve efficiency is much more difficult and costly than getting it right the first time. That’s why improving the performance of new homes is vital to ensure our homes can provide comfortable, affordable and climate-resilient shelter into the future.
With mandatory changes to energy efficiency on the way, if you’re thinking about building or renovating a home, now is the ideal time to talk to your design team and builder about planning for a 7-star (or better) home.
What’s changing?
The updated requirements call for a minimum energy efficiency for a new home’s building shell of 7 stars out of a possible 10 through the Nationwide House Energy Rating Scheme (NatHERS). The rating measures the amount of energy needed to heat and cool a home, with adjustments for different climate zones. In most locations, the increase means it will take 20 to 25 per cent less energy to heat and cool a home.
The changes to the NCC will also introduce a new ‘Whole of Home’ approach. Alongside the minimum 7-star rating for thermal efficiency, a new ‘energy budget’ will be applied that takes into account efficient appliances and solar. The energy budget sets a maximum annual energy use for heating and cooling, hot water and lighting (and swimming pool and spa pumps where relevant) that can be offset by adding solar PV to the home.
A Whole of Home assessment can predict whether a home will be net zero for operational energy (Net Zero Carbon), meaning that over a year it produces the same amount of energy as it consumes (or even more) – definitely something to aim for.
Choosing energy-efficient appliances such as heat pumps for hot water can help meet the new Whole-of-Home annual energy budget. Image: Arden Homes.This move to a Whole of Home approach is urgently needed to support homes to reduce ongoing greenhouse gas emissions, and the energy efficiency industry agrees. In addition to the upgraded 7-star minimum, homeowners will for the first time receive a report that will predict their ongoing energy use and associated emissions, with their house benchmarked against a net zero energy target. This will be a potent driver towards net zero housing.”
The new NCC also includes a universal design standard based on Livable Housing Australia’s Silver Level guidelines, to increase the stock of homes with accessibility features and support flexibility of use for all Australians.
Will it cost more to design to 7-stars?
In most cases yes. Designing with passive solar principles is one of the most important things to consider when building a 7-star home. As the requirements for the energy performance of new homes increase, optimising the orientation of the home by placing living areas to the north and providing appropriate shading from summer sun will continue to be the most cost-effective way to maximise the star rating.
Architects and designers will know the importance of considering orientation and the local climatic conditions when designing an energy-efficient home.
Appropriate design will differ from house to house depending on factors like climate, orientation and construction materials, but in most cases, the new standard can be met through relatively simple and low-cost changes early in the design process. The key differences between a 6-star and 7-star rating for a home may include taking better advantage of opportunities to heat the home passively in winter while shading it in summer. As well as good orientation for solar gain when it’s desired, this can be done using improved ceiling, wall or underfloor insulation to suit the local climate, and high-performance glazing to better insulate the home from heat loss in winter and heat gain in summer. Homes that have poor orientation will need to work harder to achieve 7-stars through increased levels of insulation, better glazing, careful consideration of window sizing and smarter floor plans.
The below factors will help achieve 7 stars:
- Reducing the number of levels or split levels of a dwelling - single level is best
- North orientated living / kitchen spaces
- Higher insulation to walls, floors and ceilings
- Construction materials with inherent R-values, such as polystyrene
- Simple square or rectangular floor plans.
- Lower ceiling heights, with minimum voids, raked ceilings.
- High performing double glazed windows
- Greater distance from neighboring buildings and obstructions
What about the builders?
Some building industry groups have expressed concern that adjusting their practices to build to 7-stars will be difficult, but learnings from the introduction of the 6-star standard suggest that industry will in fact adjust quickly and at low cost.
One key issue will be ensuring that the finished home performs as the energy rating of its design predicts. In Victoria, the state government already runs a program to improve the capacity and capability of the building industry through training and rebates for builders who build their new homes to a 7-star rating with a Whole of Home assessment.
Going beyond 7-stars
As 7-stars become the new minimum standard, achieving better than the minimum will become easier and more cost-effective. The new regulations are a step change towards even better-performing homes, with the goal (according to the national Trajectory for Low Energy Buildings) being homes that are “zero energy and carbon ready”, or in other words Net Zero Carbon or even True Zero Carbon, offsetting embodied energy as well as operational. Additionally, future-proofed homes should provide for electric vehicles by including electrical wiring to the garage or carport for the installation of an EV charger in the future.
As buildings become more efficient and better sealed, it also becomes important to consider ventilation to ensure fresh internal air. This can be done by designing for natural cross and stack ventilation through windows opened and closed at appropriate times through the day, or by installing a mechanical ventilation system with heat recovery for extra efficiency. Such a system becomes important in very airtight homes with less than five air changes per hour at 50 pascals (ACH50). The NCC effectively requires new homes to be under 10 ACH50, but post-build airtightness testing is not yet mandatory.
Conclusion
The change in the minimum standard from 6-star homes to 7-star homes with a Whole of Home energy budget will ultimately ensure that the homes that are built today and into the future are more resilient to climate extremes and have lower running costs. Improvements to the energy efficiency of new homes will have long-lasting impacts for future generations and bring us all one step closer to homes that are truly net zero for carbon emissions, reducing our overall carbon footprint and impact on the planet.
• How well are you prepared for the upcoming changes?
• Do you know what you need to do comply with these new requirements?
• If you’re not sure, please Contact us.
The new provisions intends to improve the efficient energy use in building design and construction, as well as the energy usage by key equipment installed in a building. This is the requirement of 7 Star rating and also Whole of Home energy efficiency compliance.