What NatHERS measures

Thermal performance and Whole of Home energy use

A NatHERS thermal rating assesses the design and construction of a home's building shell. This includes its roof, walls, floors, windows, insulation, orientation, shading and other features that influence heating and cooling demand.

The result is expressed as a rating from 0 to 10 stars. A higher rating means the home is expected to require less energy for heating and cooling under the standard assumptions used in the assessment.

The rating is calculated using accredited software and the climate data for the property's location. It is a model rather than a measurement of how the completed home performs in everyday use.

What the star levels mean in practice

Lower ratings

The home is expected to require more heating and cooling to maintain comfortable indoor temperatures.

Mid range ratings

The building shell is expected to perform better than a lower rated home, although the result still depends on the design, construction and local climate.

Higher ratings

The home is expected to require less heating and cooling under the assessment assumptions.

10 stars

The home is modelled to require little or no energy for heating and cooling to maintain comfortable temperatures.

Whole of Home energy rating

The Whole of Home assessment produces a separate score out of 100. It considers the expected energy use of major fixed systems and appliances, including heating and cooling equipment, hot water, lighting, pool and spa equipment, cooking appliances, solar panels and batteries.

The thermal star rating and Whole of Home score answer different questions. The star rating assesses the building shell, while the Whole of Home score considers the home's broader energy use and any onsite generation.

Actual energy bills will still depend on household size, behaviour, appliance use, electricity tariffs and the performance of the completed home.

A NatHERS assessment predicts performance using standard assumptions. It does not guarantee a particular level of comfort or a particular energy bill.

Current requirements in Queensland

Since 1 May 2024, Queensland's Modern Homes standards have generally required new homes to meet a 7 star energy equivalence outcome and a Whole of Home energy budget.

Queensland also provides variations and alternative compliance pathways. These can include different requirements for some small homes and raised floor construction, as well as credits for eligible outdoor living areas.

The applicable requirement depends on the building type, design, approval date and compliance pathway. Buyers should check the approved documentation rather than relying only on a marketing claim that a home is 7 star.

Why it matters for buyers

Useful information, with some limitations

A NatHERS rating can help a buyer understand how the home's building shell was expected to perform when it was assessed. This can be particularly useful for a new build, a recently completed home or a substantial renovation.

A higher thermal rating may indicate lower heating and cooling demand, but it does not assess the home's condition, construction quality or every factor that affects comfort.

It also does not establish actual running costs. Energy bills depend on the people living in the home, the systems and appliances installed, how they are used, electricity prices and any solar generation or battery storage.

Understanding the local climate

NatHERS uses climate data for the property's location. In and around Noosa, shading, ventilation, insulation, glazing, orientation and protection from unwanted heat gain can all influence thermal performance.

The appropriate design response can vary between coastal, suburban and hinterland properties. Buyers should consider the rating alongside the home's orientation, airflow, exposure, construction and condition.

What to verify

For a new or recently completed home, ask:

  • Was a NatHERS assessment used as the compliance pathway?
  • What thermal star rating was achieved?
  • Is an accredited NatHERS certificate available?
  • Is a Whole of Home rating or energy budget document available?
  • Which plans and specifications were assessed?
  • Were changes made during construction?
  • Do the installed insulation, glazing, shading and fixed systems match the approved documentation?

A NatHERS certificate records the design that was assessed. Buyers should not assume that the certificate alone confirms every element was installed or constructed exactly as documented.

Ratings for existing homes

NatHERS has expanded beyond new homes to include Home Energy Ratings for existing homes. The Home Energy Rating service officially launched in July 2026, with assessor training, accreditation and assessment availability continuing to expand.

An existing home assessment can provide a thermal star rating, a broader Home Energy Rating and practical upgrade advice.

Availability may vary as the service develops. Buyers interested in an assessment should confirm whether an accredited assessor is available in their area and what the assessment will include.

Local context

NatHERS and established homes around Noosa

Many established homes were built before NatHERS ratings became common and may not have a certificate. The absence of a rating does not establish whether a home will be comfortable, efficient or suited to the local climate.

Older homes can still have useful passive features such as deep eaves, shaded openings, high ceilings and cross ventilation. They may also have limited insulation, inefficient glazing or areas where heat and air can move through the building shell.

For an established property, the rating should be considered alongside a physical assessment of the home's orientation, shading, ventilation, insulation, glazing, construction and condition.