The Nationwide House Energy Rating Scheme (NatHERS) is Australia’s national system for measuring the thermal performance of residential buildings. It predicts how comfortable a home will be to live in – without relying heavily on mechanical heating or cooling – based on its design, layout, materials and orientation.
Rather than rating products or technologies, NatHERS assesses how a home performs as a system, using computer simulations to estimate energy demand for heating and cooling under local climate conditions.
It uses robust, CSIRO-developed, and government-endorsed simulation tools and trained assessors, but it remains a predictive model, not a measured outcome. Performance on paper can diverge from real-world results depending on construction quality, occupant behaviour and systems installed later.
What it measures
NatHERS focuses narrowly and deliberately on thermal performance, not sustainability as a whole.
It assesses:
Energy – Predicted heating and cooling energy demand of a dwelling
Carbon (Indirectly only) – lower energy demand can reduce operational emissions, but carbon is not explicitly calculated
Thermal comfort – How well a home maintains comfortable indoor temperatures across seasons
Building fabric performance –Walls, roofs, floors, windows, insulation, shading, air movement and glazing
Climate responsiveness – Performance is modelled against specific Australian climate zones
Design outcomes – Orientation, layout, room zoning, window placement and shading strategies
What it does not measure
This is where NatHERS is often misunderstood.
NatHERS does not assess:
- Embodied carbon or lifecycle impacts
- Material toxicity or chemical content
- Water use or water efficiency
- Renewable energy systems (e.g. solar PV)
- Actual operational energy use once occupied
- Construction quality or installation accuracy
- Broader environmental or social sustainability outcomes
A high NatHERS rating does not automatically mean a home is ‘sustainable’ – but it does mean you have a building that is thermally efficient by design.
Who it’s for
NatHERS is primarily used by:
Architects and designers
To test and refine passive design strategies early in the design process
Builders and developers
To demonstrate compliance with the National Construction Code (NCC)
Homeowners
To understand comfort, running costs and design trade-offs
Policy and regulators
As a consistent national benchmark for residential energy performance
It is not consumer-facing in the way other product certifications are.
Geographic relevance
The NatHERS system was developed in Australia, for Australian building standards, as such it’s:
Australia-specific: NatHERS is tailored to Australian climate zones and housing typologies
Climate-dependent by design: The same house design will score differently in Darwin, Melbourne, or Hobart
Not transferable internationally: Ratings are not comparable with overseas systems like Passivhaus or LEED
