What is NatHERS?

Fact Checked

What is NatHERS?

The Nationwide House Energy Rating Scheme (NatHERS) is a 10-point star ratings system measuring the energy efficiency of a home — specifically its thermal efficiency.

This scheme was implemented by the Australian Government to help uphold design standards, make homes more energy efficient and climate resilient, closing the gap with Australia’s 2050 net-zero emissions target.

How does NatHERS work?

When rating a new home or renovation, a NatHERS assessor relies on accredited software to assess a home’s thermal efficiency based on factors such as:

• Building materials
• Methods used
• Size of rooms
• Layout and orientation of the home
• Whether the home is in a position to utilise natural shading and breezes
• Climate zone information.

Each home is then given a NatHERS rating: a thermal rating system ranging from zero to 10 stars. The more stars awarded, the more ‘thermally comfortable’ a home is, meaning less electricity is needed to heat and cool it.

Conversely, a home with a zero-star rating would be too hot in summer and too cold in winter, requiring a lot of energy to maintain a comfortable temperature.

Do take note that NatHERS is currently expanding its coverage to include existing homes.

Whole of Home rating

Recently, NatHERS has been updated to include a separate ‘Whole of Home’ rating, which evaluates the following criteria:

• The cost to run major appliances (including their energy consumption)
• The impact of rooftop solar and solar batteries
• Greenhouse gas emissions.

The ‘Whole of Home’ rating is scored based on a scale between zero and 100. The higher the rating, the less energy it consumes and the lower its carbon footprint. Homes with solar that generate more energy than they consume can score a rating above 100.

Both ratings are then consolidated onto a NatHERS certificate.

How does NatHERS affect me?

The entire NatHERS certification scheme is intuitively designed so that the higher your star and ‘Whole of Home’ ratings, the lower your energy bills.

Having a high NatHERS rating means that your property will be more thermally efficient, allowing you to cut back on your air-conditioning/heating use without foregoing a comfortable temperature.

The same applies to a ‘Whole of Home’ rating. A higher score translates into a home that uses less electricity. In turn, you’ll be spending far less on your energy use.

Is a NatHERS rating compulsory?

Because NatHERS supports the energy efficiency standards outlined under the National Construction Code (NCC), the entire NatHERS scheme is mandatory for new constructions or renovations.

To get NatHERS certified, your builder or contractor must contact a NatHERS accredited assessor, a company trained and accredited to rate your home’s thermal efficiency.

An assessor can typically be found by reaching out to the following three Assessor Accredited Organisations (AAO):

• The Australian Building Sustainability Organisation (ABSA)
• Design Matters National
• House Energy Rates Association (HERA).

Alternatively, you can Google search ‘NatHERS assessor’ in your state.

Do take note that new homes and renovations must meet these standards outlined in the NCC:

• NatHERS star rating: Seven out of 10 stars
• NatHERS Whole of Home rating: 60 out of 100.

Other states and territories may have other certification systems to determine these rating features, but NatHERS is the most common system for accreditation in health, safety and sustainability in Australia.

According to the government’s NatHERS website, about 90% of new home designs in Australia are assessed using NatHERS.

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How much does a NatHERS star rating and certificate cost?

For most properties, you can expect to pay at least a few hundred dollars for an assessment, but you should be able to receive a free quote.

The cost of a NatHERS star rating and certificate will vary depending on the size and design of the property.

What is the difference between NatHERS and BASIX?

The NCC does not apply to NSW. However, the New South Wales Government runs the Building Sustainability Index (BASIX), which looks closely at three specific areas of the home: water, thermal and energy.

BASIX uses a simulation method to determine whether or not a house will meet the energy, water and thermal minimum sustainability targets in NSW.

Similar to NatHERS, a BASIX certificate is required when lodging an application for development in NSW. However, a NatHERS star rating can be used to determine the target heating and cooling performance of a home under a BASIX certificate.

How to make your home more energy efficient

If you are currently designing your new build and looking to make it more energy efficient, there are some minimal to no extra cost changes you can implement to ensure your home receives a strong NatHERS rating.

Improvements like:

• Adequate ventilation: Designing your home to optimise natural ventilation is a significant way to help the thermal rating on your NatHERS assessment.
• Air movement: Installing ceiling fans in your home will help to move cool or warm air where you want it.
• Doors that close off unused sections of the house: This allows you to heat or cool smaller parts of your home, which reduces energy usage.
• Proper insulation: Insulating your home will help keep the cool air inside and the heat outside during summer and the heat inside when it’s winter.
• Window glazing: This helps to minimise heat loss and heat gain throughout the year.
• Energy efficient lighting: Choosing LED bulbs over traditional bulbs will help increase the energy efficiency of your home.

Compare cheap electricity plans

There are also other ways you can make your home more energy efficient internally. Switching your lightbulbs to LED and choosing appliances for your home that have a high energy efficiency rating are simple ways you can ensure your household uses less energy.

If you’re moving into a new building or simply looking to save a few dollars on your electricity bill, it may be worth comparing cheap energy plans in your area with Canstar Blue’s free energy comparison tool. You can start by comparing your current energy plan with the cheapest on the table below.