As the construction industry strives to enhance environmental sustainability for Australian homes, certifications like NatHERS and BASIX play a crucial role in achieving these goals.
These sustainability assessments ensure that buildings meet specific environmental standards, focusing on energy efficiency, water conservation, and thermal comfort.
While both BASIX and NatHERS contribute to improved energy efficiency, they differ in scope, application, and requirements.
This guide explores the key differences, when each is required, cost considerations, and frequently asked questions to help homeowners, builders, and designers navigate compliance effectively.
Table of Contents
Overview of BASIX (Building Sustainability Index)
BASIX is a mandatory sustainability assessment tool used specifically in New South Wales (NSW) to ensure that new residential buildings meet the minimum standards for water and energy efficiency.
The comprehensive assessment, which must be included with your development application, aims to drive broader sustainability outcomes, such as:
- Reducing water usage: By promoting the use of water-efficient fixtures (toilets, showers, taps), rainwater harvesting systems, and greywater recycling options.
- Minimising energy use: Encouraging the use of energy-efficient appliances, solar hot water systems, and high-performance insulation.
- Improving indoor air quality: Promoting good ventilation and minimising the use of harmful building materials.
By setting and enforcing these sustainability targets, BASIX plays an important part in reducing the environmental impact of new homes in NSW and promoting more sustainable and environmentally responsible building practices.
Overview of NatHERS (Nationwide House Energy Rating Scheme)
NatHERS is a national scheme used to measure the thermal efficiency of homes, with a rating system from 0 to 10 stars.
NatHERS utilises software tools to model and assess a building’s design for energy efficiency, considering factors such as:
- Insulation: The type and thickness of insulation in walls, ceilings, floors, and roofs. Adequate insulation plays a crucial role in minimising heat loss in winter and heat gain in summer.
- Orientation: The building’s orientation relative to the sun’s path. Proper orientation can maximise solar gain in winter for passive heating and minimise solar heat gain in summer to reduce cooling loads.
- Glazing: The type and size of windows, including their glazing type (single-pane, double-pane, low-E glass) and shading devices. High-quality glazing can significantly impact a home’s energy efficiency.
- Climate: The local climate conditions, including temperature variations, wind patterns, and solar radiation, are considered when assessing a building’s energy performance.
- Building materials: The thermal properties of building materials, such as brick, timber, and concrete, influence how well the building retains or loses heat.
These NatHERS ratings empower homeowners and builders to make informed decisions about design choices and building materials, ultimately leading to more energy-efficient and comfortable homes.
When is NatHERS Required?
A NatHERS assessment is required when:
- Complying with the National Construction Code (NCC) energy efficiency standards.
- Providing a thermal comfort rating for new homes or major renovations.
- Meeting state-based energy efficiency regulations outside of NSW.
Most new homes across Australia must achieve at least a 7-star NatHERS rating under the NCC 2022 update.
When is BASIX Required?
A BASIX certificate is mandatory for all new residential developments and major renovations in NSW. It is required for:
- New homes, townhouses, and apartments.
- Renovations costing $50,000 or more.
- Secondary dwellings, such as granny flats.
BASIX must be included in development applications to ensure energy, water, and thermal performance targets are met.
Using NatHERS to Comply with BASIX Thermal Comfort Targets
BASIX includes thermal comfort requirements to ensure comfortable living conditions within the home.
To demonstrate compliance with these requirements, builders can utilise the NatHERS assessment.
BASIX employs a sophisticated simulation method to predict indoor temperatures throughout the year.
This simulation considers various factors, including:
- Building orientation and shading
- The type and thickness of insulation in walls, ceilings, and floors
- The type and size of windows, including their glazing (single-pane, double-pane, low-E glass) and shading devices
- The specific climatic conditions of the region where the building is located
By achieving a high NatHERS star rating, which indicates a high level of energy efficiency, builders can effectively demonstrate compliance with BASIX thermal comfort requirements.
Using a NatHERS assessment can be more cost-effective than using the full BASIX DIY method, as it allows for more flexibility in design and construction while still meeting the required performance standards.
Key Differences Between NatHERS and BASIX
Feature | BASIX (NSW Only) | NatHERS (National) |
|---|---|---|
Scope |
Sustainability across energy, water, and thermal comfort. |
Thermal efficiency and energy performance. |
Application |
Mandatory in NSW for new builds and major renovations. |
Used nationwide to comply with the National Construction Code. |
Assessment Method |
Online tool with preset requirements for energy, water, and comfort. |
Software-based simulation of heating and cooling energy use. |
Outcome |
BASIX Certificate required for DA approval. |
Star rating (0-10) used for energy compliance. |
Cost |
From $240 for single storey, $320 for double storey, $180 for renovations and alterations (varies by project size and complexity). |
$200 - $300 for single storey dwellings, $300 - $500 for double storey (depending on home design and consultant fees). |
While both certifications focus on sustainability, there are key differences between NatHERS and BASIX:
Scope and Coverage
NatHERS primarily focuses on thermal comfort, analysing heating and cooling needs to reduce energy consumption.
BASIX, on the other hand, takes a more holistic approach, covering energy efficiency, water conservation, and thermal comfort.
Geographic Application
NatHERS is used nationally across Australia, while BASIX is specific to NSW and required for all residential developments in that state.
Assessment Criteria and Focus Areas
NatHERS concentrates on the building’s ability to maintain comfortable temperatures with minimal energy, using star ratings based on thermal performance.
BASIX encompasses energy, water, and thermal comfort with specific targets for each, providing flexibility in how builders meet these targets.
Method of Assessment
NatHERS utilises detailed software modelling to simulate energy requirements based on design.
BASIX includes online assessment and data entry via the BASIX online tool, focusing on achievable design elements for water and energy reduction.
Cost Comparison: NatHERS vs BASIX Certificates
The costs associated with NatHERS assessments and BASIX certificates can vary depending on the type and complexity of the project.
The below pricing structures provide a guide to typical fees you can expect to pay for a new residential project, however for a more accurate quote, please contact us regarding your specific project.
NatHERS Certificate Costs
The cost for a NatHERS certificate starts at $200 + GST for a single-storey dwelling. Prices can increase depending on the size and complexity of the project:
- Single Storey Dwellings: $200 – $300 + GST
- Double Storey Dwellings: $300 – $500 + GST
NatHERS certificates are primarily used for energy efficiency ratings, and the final cost will depend on the specific energy modelling needed to meet the requirements.
BASIX Certificate Costs
A BASIX certificate is required for all new homes, renovations, and some other residential projects in New South Wales. The cost varies based on the project’s size and complexity:
- Single Storey New Homes: From $240
- Double Storey New Homes: From $320
- Renovations & Alterations: From $180
- NSW Department of Planning & Infrastructure Fees:
- New Homes: $50
- Alterations/Additions: $25
- Additional Fees: For projects requiring NatHERS simulation, an extra $30 may apply.
In addition to the costs listed above, a BASIX certificate also requires an assessment using an online tool, and the certificate confirms that the home meets government-set sustainability targets for water use, energy efficiency, and thermal comfort.
How NatHERS and BASIX Complement Each Other
NatHERS and BASIX are two complementary certifications that, despite their differences, work together to promote energy-efficient and thermally comfortable buildings.
One key area of overlap between the two is their emphasis on thermal comfort.
While NatHERS focuses specifically on temperature stability, BASIX takes a broader approach, considering overall building efficiency.
This complementary focus enables developers to create buildings that not only provide stable temperatures but also minimise energy consumption.
The combination of NatHERS and BASIX can also have practical benefits for developers. Achieving a high-star rating from NatHERS can contribute to compliance with BASIX’s thermal comfort standards.
This, in turn, can lead to cost savings during construction, as developers may be able to use less stringent insulation and glazing requirements.
Also, when NatHERS and BASIX are used together, their combined focus on thermal efficiency and energy targets can result in even lower energy usage and cost savings on energy bills.
By leveraging the strengths of both certifications, developers can create buildings that are not only comfortable and efficient but also environmentally sustainable.
Deciding Which Certification You Need
The choice between NatHERS and BASIX depends on several key factors.
In New South Wales, BASIX is mandatory for all new residential builds and significant renovations. In other states, NatHERS compliance (or a similar state-specific energy standard) is typically required.
For new homes, utilising both NatHERS and BASIX can offer significant benefits.
NatHERS can effectively demonstrate compliance with the thermal comfort requirements outlined within the BASIX framework, often providing a more cost-effective approach compared to using the full BASIX DIY method.
It’s important to consider the long-term implications of each certification.
NatHERS provides a nationally recognised star rating system, which can enhance a home’s marketability and appeal to energy-conscious buyers.
BASIX compliance ensures that the building meets specific sustainability targets set by the NSW government, contributing to a more sustainable living environment and potentially increasing the home’s long-term value.
FAQs: Common Questions About BASIX & NatHERS
Can a NatHERS assessment satisfy BASIX energy requirements?
No, a NatHERS assessment does not completely satisfy all BASIX energy requirements. While a NatHERS rating focuses on thermal comfort by assessing how efficiently a home manages heat, it only addresses the energy efficiency aspect.
BASIX, on the other hand, includes additional targets for water conservation, greenhouse gas reduction, and thermal comfort.
A NatHERS rating can be used to meet the thermal comfort portion of the BASIX energy requirements, but BASIX also requires other factors like water usage, energy efficiency measures (e.g., appliances, lighting), and emissions reductions that NatHERS does not cover.
Therefore, while there is overlap, BASIX has a broader scope that encompasses more sustainability elements.
What is a good NatHERS star rating?
A 7-star rating is considered the minimum for a home to meet current building standards for energy efficiency.
However, higher ratings—such as 8 or 9 stars—indicate better energy efficiency, leading to reduced heating and cooling costs over time.
Homes with higher ratings tend to be more comfortable to live in year-round because they are better at maintaining consistent indoor temperatures without relying heavily on heating or cooling systems.
In addition to lower energy costs, higher star ratings often correlate with better environmental performance, contributing to reduced greenhouse gas emissions.
For homeowners, a higher NatHERS rating can mean savings in both energy bills and a more comfortable living environment.
Do all states require NatHERS?
While the Nationwide House Energy Rating Scheme (NatHERS) is a nationally recognised system for assessing the thermal performance of residential buildings, its mandatory application varies across Australian states and territories.
However, states and territories have the authority to implement and interpret the NCC, and they may allow alternative compliance pathways:
- Queensland: Queensland utilises the Queensland Development Code (QDC), which incorporates energy efficiency requirements. While NatHERS is a common method, the QDC allows for alternative solutions that meet the required performance levels.
- Victoria: Victoria strongly relies on NatHERS for assessing thermal performance. However, there are provisions for alternative solutions, particularly for complex designs or renovations where a standard NatHERS assessment may not be suitable.
- Western Australia: Western Australia employs its own energy efficiency regulations. NatHERS ratings are accepted and commonly used, especially for demonstrating thermal performance. However, compliance can also be achieved through other methods that meet the state’s specific requirements.
It’s crucial to note that the specific requirements and accepted methodologies can change. Therefore, it’s always recommended to consult the relevant building authority in each state or territory for the most up-to-date and accurate information.
How do NatHERS and BASIX impact home design?
Both NatHERS and BASIX significantly influence the design and layout of a home, but in different ways:
BASIX impacts decisions around water use, energy consumption, and thermal comfort. For example, you might need to install energy-efficient appliances, incorporate solar panels, or include high-efficiency insulation to meet BASIX requirements.
It also emphasises water-saving features such as rainwater tanks or low-flow fixtures.
NatHERS focuses primarily on passive design principles. These principles aim to reduce a home’s reliance on artificial heating and cooling.
Design elements such as the home’s orientation, window placement, and glazing can all be adjusted to improve a building’s energy performance under the NatHERS rating system.
For example, maximising northern sunlight and using shading to reduce heat gain in summer can improve thermal comfort.
These two systems work in tandem to ensure that homes are not only energy-efficient but also comfortable and sustainable in the long term.
Can my home comply with both BASIX and NatHERS?
Yes, it’s quite common for homes in New South Wales to comply with both BASIX and NatHERS. In fact, many projects are required to meet both to ensure that they satisfy the sustainability requirements set by the state.
NatHERS is primarily concerned with thermal performance, providing a rating based on the home’s design (e.g., building envelope, insulation, ventilation, and shading).
BASIX takes a broader approach, covering not just thermal comfort but also water conservation, energy use, and greenhouse gas emissions.
For example, a home may meet BASIX’s thermal comfort targets through NatHERS, but it will still need to meet other BASIX requirements for water and energy efficiency.
This is why most new homes in NSW need both a NatHERS rating and a BASIX certificate.
What are the latest NatHERS and NCC changes?
There are several important changes coming to NatHERS and the National Construction Code (NCC) that will impact home design and energy performance:
Mid-2025: The NatHERS system will expand to include ratings for existing homes, enabling owners of older homes to assess and improve their energy efficiency.
New energy performance requirements: The NCC will introduce new Whole of Home energy performance targets. For example, standalone homes must achieve a minimum score of 60/100 for energy efficiency.
These targets aim to ensure that all homes, whether new or existing, are more energy-efficient and contribute to the reduction of carbon emissions across Australia.
This will likely encourage design changes that improve a home’s overall energy performance, including better insulation, more efficient windows, and solar power integration.
Choosing The Right Certification For Your Project
NatHERS and BASIX are two essential sustainability certifications in Australia.
While they have different scopes, assessment criteria, and geographic applications, they complement each other in promoting sustainable building practices.
If you’re unsure about which certification is right for your project, consider getting in touch with our consultants.
At Green Choice Consultancy, our experts can guide you through the process, ensuring compliance and optimal efficiency.
Contact us on 1300 864 944 or email energy@greenchoiceconsulting.com.au.
