The AccuRate Software is an enhanced version of the earlier NatHERS software, which has been in use in Australia for over 10 years. It is a rating tool that assigns a star rating to a residential building (a detached or semi-detached house, unit, townhouse, or apartment) based on its calculated annual heating and cooling energy requirements (not energy consumption: i.e. equipment efficiency is not taken into account).

The heating and cooling energy requirements are calculated hourly over a period of one year, using a year of real weather data appropriate for the location.

The following aspects of occupant behaviour are taken into account:

• Hours of heating and cooling
• Heating and cooling thermostat settings
• Operation of windows and other openings to increase ventilation
• Operation of adjustable outdoor window shading
• Operation of indoor window coverings