Achieving 7-Star Energy Ratings in New Australian Homes
The Australian building industry is on the cusp of a significant shift towards more energy-efficient housing. With the upcoming changes to the National Construction Code (NCC) in 2022, new homes across Australia will be required to meet a minimum 7-star energy rating under the Nationwide House Energy Rating Scheme (NatHERS). This article explores what this change means for homeowners and builders, and provides practical insights on how to achieve a 7-star energy rating in new Australian homes.
Understanding NatHERS and Energy Ratings
The Nationwide House Energy Rating Scheme (NatHERS) provides Australian homes with a star rating out of 10 based on their energy efficiency. This rating reflects how well a home can maintain comfortable temperatures without excessive reliance on artificial heating and cooling. Currently, the minimum standard for most new homes is a 6-star rating, but this is set to increase to 7 stars with the new regulations.
A 7-star rated home is estimated to use about 30% less energy for heating and cooling compared to a 6-star home. This improvement can lead to significant savings on energy bills and a reduced carbon footprint, making it an attractive prospect for both homeowners and the environment.
Key Strategies for Achieving a 7-Star Rating
1. Optimise Home Orientation
One of the most crucial factors in achieving a 7-star rating is proper home orientation. In Australia, this typically means:
- Positioning living areas to face north where possible
- Minimising west-facing windows to reduce heat gain in summer
- Using eaves and other shading devices to control sunlight entry
Correct orientation can significantly reduce the need for artificial heating and cooling, forming the foundation of an energy-efficient home.
2. Improve Insulation
Upgrading insulation is a key strategy for achieving a 7-star rating. This includes:
- Using high-quality bulk insulation in walls, ceilings, and floors
- Addressing thermal bridges in the building envelope
- Considering double-brick or reverse brick veneer construction for improved thermal mass
For instance, Ecoliv, a leading sustainable home builder in Australia, recommends using a combination of bulk insulation and reflective foil insulation to achieve optimal thermal performance.
3. Upgrade Glazing
Windows are a significant source of heat gain and loss in homes. To achieve a 7-star rating, consider:
- Installing double or triple glazing
- Using low-e glass to reduce heat transfer
- Ensuring proper sealing around windows and doors
According to the Australian Government’s Your Home guide, high-performance glazing can reduce heat loss by up to 40% compared to single glazing.
4. Incorporate Passive Design Principles
Passive design principles work with the climate to maintain a comfortable temperature in the home. Key strategies include:
- Using thermal mass to absorb and release heat
- Designing for cross-ventilation to promote natural cooling
- Incorporating shading devices like pergolas and deciduous trees
These principles can significantly reduce the need for artificial heating and cooling, contributing to a higher energy rating.
5. Choose Energy-Efficient Systems and Appliances
While not directly part of the NatHERS assessment, energy-efficient systems and appliances can contribute to overall home performance. Consider:
- Installing solar panels and battery storage
- Opting for energy-efficient heating and cooling systems
- Choosing LED lighting and energy-efficient appliances
NewGen Solar, an Australian solar provider, notes that homes with solar systems can achieve higher energy ratings and significantly reduce power bills.
The Benefits of a 7-Star Home
Achieving a 7-star energy rating offers numerous benefits:
- Lower Energy Bills: A 7-star home can reduce energy costs by up to 20% compared to a 6-star home.
- Improved Comfort: Better insulation and design lead to more stable indoor temperatures year-round.
- Increased Property Value: Research from the University of Melbourne shows that homes with higher energy ratings can command a price premium of up to 9.4%.
- Reduced Carbon Footprint: Energy-efficient homes contribute to lower greenhouse gas emissions.
- Future-Proofing: As energy standards continue to rise, a 7-star home is better positioned to meet future requirements.
Challenges and Considerations
While the benefits of 7-star homes are clear, there are some challenges to consider:
- Initial Costs: Achieving a 7-star rating may involve higher upfront costs, although these are often offset by long-term savings.
- Design Constraints: Some design features may need to be modified to meet energy efficiency requirements.
- Regional Variations: Different climate zones in Australia may require different strategies to achieve a 7-star rating.
As Australia moves towards more sustainable housing, achieving a 7-star energy rating will become the new standard for new homes. By focusing on orientation, insulation, glazing, passive design, and energy-efficient systems, homeowners and builders can create comfortable, cost-effective, and environmentally friendly homes that meet or exceed this standard.
For those embarking on a new home build or major renovation, engaging with a NatHERS accredited assessor early in the design process is crucial. These professionals can provide valuable insights and recommendations to help achieve the desired energy rating while maintaining design integrity.
As we face the challenges of climate change and rising energy costs, 7-star homes represent a significant step towards a more sustainable and comfortable future for Australian homeowners. By embracing these higher standards, we can create homes that are not only better for the environment but also more enjoyable and economical to live in.