Key modelling inputs

To ensure calculations are accurate, representative of Australian conditions and are comparable across different types of housing, the Software Protocol requires all NatHERS accredited software tools to meet strict performance standards and requirements for variables including (but not limited to):

• local climate and weather (including temperature, humidity, wind and sun)
• thermal resistance and capacitance of building materials
• window glazing values
• occupancy patterns (including internal heat loads, typical occupancy times and occupancy behaviour)
• window coverings (which are standardised for all ratings, noting they are likely to change over the life of the building)
• different types of zones in the house and whether they are conditioned/unconditioned
• thermostat settings (temperatures at which artificial heating/cooling is no longer required to achieve thermal comfort, noting this varies depending on climate zone)
• shadowing/overshadowing by adjacent buildings and features
• size of the building being assessed (noting smaller buildings generally have a larger wall surface area than bigger buildings)

There are currently four software tools accredited for use under NatHERS, all based on the CSIRO calculation engine, Chenath (v3.21):

• AccuRate Sustainability v2.4.3.21 SP1
• FirstRate5 v5.3.2b (3.21)
• BERS Pro v4.4.1.5 (3.21)
• HERO v3.0.1.1 (3.21)