Were you inspired by Sustainable House Day and keen to get stuck into building or renovating your own sustainable home? Understanding how energy rating tools can be used in the planning stage will help you push your home’s thermal performance towards a high star rating.

When building or renovating for sustainability, there is a myriad of technical information to get your head around. Like how orientation and layout can help to naturally heat and cool your home, and how the thermal properties of different construction materials affect comfort. With so many sustainability features to consider, it can be hard to know which ones to focus on—and how to allocate your budget.

Given the investment a new home represents, you want to know you are getting it right from the beginning. If only there were a tool that could help you compare the options. Good news – there is!

A home energy rating helps you compare the energy use of different house designs and construction materials before you build.

NatHERS home energy star ratings

The Nationwide House Energy Rating Scheme (NatHERS) is a star rating system that measures the energy efficiency of a home, using key features including design, materials and climate.

A NatHERS rating is the most common method used to show that a new home complies with the minimum energy efficiency standards in the National Construction Code. And it can help you strive for more than just the minimum.

How NatHERS predicts home energy use

NatHERS software uses computer modelling to predict how much energy is needed to comfortably heat and cool a home throughout the year. It considers many factors that contribute to thermal efficiency—from orientation and layout to construction materials, insulation and the size, type and placement of windows. The software connects with climate data from all over Australia to estimate the annual heating and cooling loads for that home in its specific location. These loads are then used to generate a star rating. The more stars, the less energy will be needed to make your home comfortable. For example, a home that achieves an 8-star rating could use over 40% less energy than a 6-star home of the same size in the same location. A 10-star home may not need any artificial cooling or heating.

Using NatHERS to test your design options

When used by an experienced assessor in the early stages of the design process, the NatHERS software can be a powerful tool to make key decisions that will impact on your home’s energy performance. Your design and material choices can then be informed by a quantifiable comparison of energy outcomes, along with other factors like personal preference, budget and local building industry conditions.

An assessor can test the impact of different options in the planning stage, well before the design and construction is finalised, including:

  • using different construction materials
  • choosing single, double or triple glazed windows or a specific window opening type and size
  • increasing or decreasing insulation
  • rotating the design on the block
  • moving windows, doors and rooms.

Make decisions like these:

Construction materials can impact how your home keeps a comfortable temperature. Compare the energy rating of the same house plan in double brick, concrete and reverse brick veneer.

Natural light is great—but windows can be a big source of heat gain and loss. Measure the impact of multiple glazing options, including size, opening type and framing.

Even small changes to the layout of your home can make a big difference to how your house performs. Rate different configurations and test their impact on predicted energy use.

Find a NatHERS Accredited Assessor

When you plan your forever home, you will have a vision of the house you want, a wish list and a budget. You know that good design can make a house cheaper to run and more comfortable to live in. But how do you know which choices will give you the best results? Seeking professional advice from a NatHERS Accredited Assessor early on will help you put broad sustainability principles into action so you can get the most of your investment, and get a high performing home you can be proud of.

To ensure you get the best advice, find a NatHERS Accredited Assessor via the NatHERS website. Accredited Assessors follow a code of practice, receive professional development and undergo quality assurance.