Guide to Energy Ratings

Energy Rating

– helps make your home more comfortable, thanks to its innovative and smart design choices


A Five Star Design Rating (FSDR) was introduced in the 1980s to award developers who have demonstrated exemplary performance in design and construction. The certification was developed by the Glass, Mass and Insulation Council of Australia (GMI Council) together with the Commonwealth Scientific and Industrial Research Organization (CSIDRO) Division of Building Research and was funded by the Federal and State government, as well as by private investors. On the other hand, the FSDR system was not widely accepted. Over time and constant development, it paved way for the development of the Nationwide House Energy Rating Scheme (NatHERS) that began in 1993.


NatHERS is based on the Victorian scheme using the CHEETAH / CHEENATH engine of the CSIRO. Other software based on this engine are FirstRate and QuickRate, Q Rate and more. In 2011, the Australian Building Codes Board introduced energy efficiency into the Building Code of Australia (BCA). The House Energy Rating was then initiated and served as an index to measure a building’s thermal performance. Since then, the system was adopted by all Australian states – a standard and mandated rating of 5 stars that leveled up to 6 stars in 2011, the minimum requirement in most of Australia.


NatHERS and its star rating scale. NatHERS stands for Nationwide House Energy Rating Scheme, a rating scheme out-of-ten score to measure a structure’s potential energy usage (heating and cooling). It serves as a ‘measuring tape’ for energy efficiency. The rating scheme is managed by the Department of the Environment and Energy and it provides extensive information about a home’s thermal performance. Ratings are based on the home’s design, construction materials, and climate. Evaluation is done by professionals using an industry-specific software. The primary reason for NatHERs is for adherence purposes, as well as to meet the mandatory requirements regulated by the National Construction Code. Aside from that, it is to evaluate the energy efficiency of various house designs to provide home owners, architects, and builders a better perspective in building a thermally ambient home. It can also be beneficial to home buyers for them to know the thermal performance of a home they are intending to buy.


How are NatHERS star ratings calculated? NatHERS star ratings are calculated using a NatHERS Accredited Software that measures indoor temperature based on data specific to that dwelling. This would include information regarding the structure’s design and patterns to the household. It would also investigate the structure’s size and function of rooms, size, and specification of openings, building materials, construction type, dwelling orientation, and location of the building. The software will then simulate and determine how much cooling or heating is needed to make occupants comfortable throughout a typical year, given the climate of the location – this way, energy consumption can be estimated. The assessment would exclude energy efficiency of appliances as it is covered by the Greenhouse and Energy Minimum Standards (GEMS). The total heating and cooling throughout the year are then converted to a star rating out of ten.


A zero star rating would mean that the structure does not do anything to alleviate the discomfort brought about by extreme weather conditions. A six-star rating, meanwhile, is satisfactory although not exemplary will pass by Australian standards. A star rating of ten, on the other hand, would mean that the structure is thermally comfortable without the need for artificial cooling or heating.


Why six stars and above? The NatHERS rating system is part of the thrust to reduce energy use and greenhouse gas emissions among Australia’s households and commercial structures. Exceptional insulation and outstanding solar passive design, architectural design and keen engineering can greatly reduce reliance on artificial cooling and heating. This way, not only the electricity bill would be greatly reduced but also the energy consumption in general.

In the pursuit of building thermally ambient and energy efficient structures, energy ratings are one of the main components of the building permit application. Energy consultants have the expertise to provide insights regarding energy efficiency and scoring high in the NatHERS star rating system.


BAYSIDE ENERGY CONSULTING is a Thermal Performance Assessor Consultancy accredited with the Building Designers Association of Victoria (BDAV) having extensive experience in maximizing energy efficiency. The firm provides fast, reliable, and accurate NatHERS Energy Reports using FirstRate5 energy rating software and Energy Compliance Assessments using Deemed-to-Satisfy provisions of the National Construction Code.


Bayside Energy Consulting provides the following services: Energy Ratings/ Thermal Performance Assessments (Base TPA Package, Standard TPA Package, Advanced TPA Package), Deemed-to-Satisfy Energy Assessments (Part 3.12 Deemed-to-Satisfy Package, Section J Deemed-to-Satisfy Package), Artificial Lighting Assessments ( Artificial Lighting Assessment, J6.2 Artificial Lighting Assessment), and External Glazing Assessments (3.12.2 Glazing Assessment, J2.4 Glazing Assessment).


The firm offers its expertise in providing a sound recommendation to improve energy efficiency. Having the right skills and tools, the firm can conduct performance assessments and advise clients on how to improve thermal efficiency and NatHERS star rating. Their expertise in data modeling and analysis provide developers and builders with cutting edge design analysis at the design stage. One of the key principles used in improving thermal performance is the passive solar building design, which includes the following strategies: thermal mass, eaves/shading and insulation.

Guide to Energy Ratings

author: Bayside Energy Consulting