The Nationwide House Energy Rating Scheme (NatHERS) is a star rating system that rates the energy efficiency of houses, based on their design, construction materials and location.
It is a national scheme, administered by the Department of the Environment and Energy, which aims to reduce energy usage and greenhouse gas impacts of residential buildings.
How NatHERS star ratings are calculated
NatHERS house ratings use computer simulations to determine the potential thermal comfort of homes on a scale of 0 to 10 stars. The more stars, the less likely the occupants will need artificial cooling or heating to stay comfortable.
Using one of the accredited software tools (BERS Pro, FirstRate5, HERO or Accurate), data is entered to develop a model simulation of the house. The Chenath engine at the back end of the software uses historical weather data, occupancy settings and internal heat loads to then determine annual heating and cooling requirements which is converted to a star rating.