Nationwide House Energy Rating Scheme (NatHERS) FAQ
WHAT IS NATHERS?
NatHERS stands for Nationwide House Energy Rating Scheme and it is a nationwide regulatory instrument by the Australian Department of the Environment and Energy to measure and scale the energy consumption of a residential building in Australia in comfortable conditions suitable for residence occupancy. The application and governance of the scheme is conducted by the NatHERS Administrator on behalf of all Australian states and territories. NatHERS star rating performance is referenced in the National Construction Code as demonstration of compliance with the energy efficiency requirements of the Building Code of Australia. You can also read more about NatHERS here.
HOW MUCH DOES A NATHERS ASSESSMENT COST
Cost of conducting a NatHERS assessment has two components. One is the fixed government fees of $30+GST per dwelling which is paid to the CSIRO HStar government web portal to generate the NatHERS certificates. This is fixed and Eco Certificates collects this fee from our clients and uses it to issue the certificates from the government website. In addition to this there is service fee by the NatHERS accredited assessor who is conducting the assessment. This service fee is based on the geometry and complexity of the assessment and therefore would vary for each project.
WHAT IS A NATHERS CERTIFICATE?
When a NatHERS thermal comfort assessment is completed by an accredited assessor, the results of the computer simulation will be exported to a government web portal named HStar. The HStar portal absorbs the simulation result files and based on that information creates a PDF file called a NatHERS certificate. This certificate summarises the results of the thermal assessment and the building components addressed in the assessment. For multi unit residential developments a summary certificate will also be generated for the entire project in addition to individual certificates for each dwelling.
HOW LONG ARE NATHERS ASSESSMENTS VALID?
NatHERS assessment certificates generated in the HStar portal are valid for 12 months. If a project is revised before 12 months passed from the date of creation, the old certificates in the HStar portal can be revised and there would be no need to pay for creation of new certificates however, after 12 months a new certificate must be purchased which would attract the government fees as well as our service fees if any.
WHAT TYPES OF BUILDINGS CAN BE MODELLED BY NATHERS?
NatHERS assessment computer modelling programs can be used to estimate the energy consumption of a residential dwelling in Australian climates. They then match it versus the NatHERS star band to report the associate comparative performance of the building. The results are in a form of star rating. Currently, computer modelling programs cannot be used to measure the energy consumption of a building outside of these boundaries.
WHAT SOFTWARES ARE USED FOR NATHERS THERMAL MODELLINGS
The following software tools in regulation mode have been accredited under NatHERS:
AccuRate v126.96.36.199 SP
BERS Pro v188.8.131.52a(3.13)
These tools are undergone the evaluation criteria of the NatHERS Software Accreditation Protocol and therefore are suitable for demonstrating compliance with the thermal performance provisions in the National Construction Code (NCC) via the Deemed-to-Satisfy pathway (i.e. clause 184.108.40.206 of NCC Volume Two; and clause J0.2 of NCC Volume One).
WHO ARE NATHERS ACCREDITED ASSESSORS?
NatHERS Accredited Assessors are professionally recognised energy assessors who are qualified in conducting house energy ratings using accredited Software. They must follow an Assessor Code of Practice as well as thermal comfort modelling protocols and guidelines. The NatHERS Administrator accredits Accrediting Organisations (AAOs) and provides guidance to ensure consistent, reliable and cost effective assessments are being provided using NatHERS software tools. AAOs are responsible for providing training, skill evaluation and support for the assessors in Australia.
WHAT INFORMATION IS REQUIRED FOR A NATHERS ASSESSMENT?
A complete summary and detailed explanation of the necessary information to conduct NatHERS assessment for various types of the buildings are provided in this page of our website.
WHAT IS THE NATHERS STAR RATING OF A DWELLING
The Nationwide House Energy Rating Scheme provides homes with a star rating out of ten based on an estimate of a home’s potential (heating and cooling) energy use. The more stars, the less likely the occupants will need active cooling or heating to stay comfortable. A range for star ratings, called a 'star band', is set for each climate zone taking into account the extremes of the local weather conditions. They compare the buildings within and between climate zones and are based on the maximum energy consumption per unit area (MJ/m2) loads for each half-star level.
WHAT IS THE RELATION BETWEEN NATHERS AND THE BASIX SCHEME?
The thermal comfort section of the BASIX online tool uses the results of a NatHERS thermal comfort modelling. It then submits them in the BASIX online tool to make sure the thermal comfort threshold requirements of the BASIX are being met. The BASIX thermal comfort protocol applies to the NatHERS simulation method of thermal comfort assessment and must be followed up in addition and on top of the national NatHERS assessment protocols. Heating and cooling loads from the thermal comfort section will be carried over as the energy demand for space heating and cooling in the BASIX energy section. The combined heating and cooling caps in BASIX are equivalent to NatHERS 5 stars for concrete slab on ground constructions of detached houses. The average heating and cooling caps applicable to multiple-dwellings projects are also equivalent to NatHERS 5 stars. Due to the interaction between the thermal comfort and energy sections (which is unique to NSW), BASIX-affected dwellings passing both the thermal comfort and energy sections are regarded as having achieved the equivalent of 6 stars.