If you’re building or renovating your home, it’s important you know about NatHERS star rating. A high star rating increases the comfortability inside your home while potentially saving you a bundle in energy costs.
NatHERS stands for the Nationwide House Energy Rating Scheme. It’s a scheme implemented by the Australian Government which aims to uphold design standards and make new homes more energy efficient. A NatHERS star rating gauges a home’s thermal performance (heating and cooling) using a 10-star rating system.
The system calculates the ‘shell frame design’ using NatHERS Accredited Software. NatHERS only accounts for the home’s design, not the household appliances plugged into the wall. As NatHERS expands, there are plans for the score to include components like hot water systems and lighting.
Whether building or renovating, a high NatHERS energy rating can help your home feel cool in the summer and warm in the winter without artificial heating or cooling. As a result, you’re using less energy and lowering your energy bills and carbon footprint, as well as supporting the move to the net-zero emissions target by 2050.
Yes, under the National Construction Code (NCC), there are minimum requirements for health and safety in the design and construction of new Australian homes, which includes NatHERS. If you’re building or renovating, it’s mandatory to get a home energy rating and NatHERS Universal Certificate issued by a NatHERS accredited assessor in order to meet Australia’s energy efficiency requirements.
The New South Wales Government doesn’t follow the NCC, but instead has a Building Sustainability Index (BASIX) initiative that assesses new buildings against sustainability requirements. BASIX considers water, thermal and energy use in its assessment. NatHERS isn’t a requirement in NSW; however, it has superior software for rating thermal performance and can be used alongside BASIX, as some companies providing BASIX certificates may offer this option. A NatHERS thermal comfort rating may cost more initially, but unlike BASIX, NatHERS will rarely suggest design changes to your home to satisfy requirements, saving you money overall.
The NatHERS rating scale goes from 0 to 10 stars – the more stars, the less energy required to heat and cool, which reduces energy costs. As of 2022, the minimum standard for the NCC in most Australian states is a 7-star energy rating.1 Anything seven and above is considered a good score.
The NatHERS software will rate the new home depending on several building design factors, including:
Including energy efficient design features at no extra cost or for minimal expense during the design phase is key to a good energy rating for a house. Some features to consider when building are:
After the NatHERS assessment, you’ll receive a NatHERS Universal Certificate with a house energy rating. It’s a government certification that indicates the energy efficiency of your home’s design. To receive it, a NatHERS accredited assessor must conduct an audit using NatHERS-approved software at an early stage of the design process.
To get a NatHERS star rating, you or your builder or architect need to go through one of the following three Assessor Accrediting Organisations (AAOs) in Australia:
If you have an already established house, getting a NatHERS star rating is still possible, but potentially a waste of money unless you’re thinking about renovating. If you are interested in having your house rated, you can find a NatHERS Accredited Assessor to review your house plans and provide an energy efficiency house rating.
It typically costs a few hundred dollars; however, prices vary depending on the complexity of the design and the overall scope (e.g. single-family home vs a multi-unit development). If you want, you could request a free quote from multiple assessors and compare.
Insulation can protect your home against cold in the winter and heat in the summer. Insulation in the roof, walls and sometimes floors help keep your home at a comfortable temperature all year round, which should reflect positively in your NatHERS star rating. Learn more about sustainable building materials.
Are you keen to lower your energy bills while reducing your carbon footprint? Check out more of our easy-to-read and informative pages on the topic:
1 Australian Government. Top Tips for Building for 7 Stars. 2022. Accessed February 2023.
