NatHERS is short for Nationwide House Energy Rating Scheme which is a national government regulatory framework that sets the performance standards for building thermal assessment computer software packages to rate the thermal comfort performance of dwellings across Australia. A certain NatHERS star rating is required according to the BCA to show compliance with the requirements of the code.
By provision of a national regulatory framework NatHERS delivers consistent and reliable energy efficiency ratings for a dwelling regardless of the software package for the assessment and the climate conditions of the development. NatHERS also sets the standards for training provider organizations and assessment procedures to train and test qualified accredited assessors to work with NatHERS thermal simulation software tools.
NatHERS regulatory framework provides legal and technical guidelines for computer thermal simulation packages for residential developments to deliver consistent and auditable results and to be accredited in a transparent and fair. NatHERS requires computer software packages to simulate how heat enters and leaves the the residential spaces of a dwelling based on the standardised building material thermal properties and normal behavioral patterns of regular families in operating the space. NatHERS currently recognizes AccuRate, FirstRate and BERS Pro as the NatHERS accredited thermal simulation software packages.
NatHERS scheme ascertains professional and educated use of NatHERS thermal simulation software packages by defining guidelines for training and evaluation of NatHERS assessors who can use and report a dwelling's thermal loads by use of a NatHERS accredited software. Currently the only organization which is accredited by NatHERS scheme to provide training and certification services for NatHERS accredited assessors is Association of Building Sustainability Assessors or ABSA which trains, test and audits the performance of ABSA Accredited Assessors in all Australian states.
NatHERS Simulation Procedures
NatHERS defines inside thermal conditions of a dwelling which brings comfort to the occupants of the dwelling. NatHERS thermal simulation packages then measure the amount of heat that must be added or removed from each zone of the house in order to keep the house comfortable throughout the year. Standard materials referenced in the NatHERS accredited software packages are used to model the geometry of the building and its orientation, climate zone and exposure conditions introduced to the software. A NatHERS star rating of 0 to 10 is then assigned to each zone as well as the whole dwelling which must be under a certain limit to satisfy the energy efficiency requirements of that dwelling based on the BCA and local and state government codes and regulations.