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Understanding energy star ratings when building your home


With utility bills sky high at the moment, investing in an energy-efficient new home can be a smart move. It means you and your family are far more likely to be comfy all year round, keeping cool in summer and toasty in winter while alleviating expenses through intelligent design choices.

How do I know if my new home will be energy-smart?

If you’re not an expert on sustainable design, luckily there’s an easy to understand rating system in place to guide your choices. You’ve probably heard of star ratings before, but might be unclear what they mean or what the associated benefits are.

Overseen by the Federal Government Department of the Environment and Energy, the Nationwide House Energy Rating Scheme (NatHERS) evaluates each property design and gives them a rating out of ten stars, based on how energy-efficient the home is.

Built into the National Construction Code, NatHERS is used by some state and territory governments to reduce the environmental impact of residential buildings*. The benefits to homeowners are long-term savings on your bills thanks to smart, sustainable design.

So the star rating functions as a handy measuring stick, giving you an instant snapshot of just how energy-efficient your home will be, increasing confidence in your design and how likely it is to keep your utility bills lower.

How is a home star-rated?

Accredited professionals assess NatHERS star ratings by using standardised software tools to evaluate insulation and solar passive design. A NatHERS rating takes into account:

  • The heating and cooling performance of the home
  • The size of the property
  • The construction materials and processes used
  • The size of rooms and the flow of the floorplan
  • The size and specification of windows, doors and archways
  • The orientation of the house and the local climate

Focused on the building blocks of the home, NatHERS does not take into account electrical appliances and air conditioning units but does factor in airflow from ceiling fans.

A NatHERS assessor also makes standard assumptions on how occupants are likely to use the property at various points during the day, and throughout the year. Plugging these variants into the software will figure out how likely the home is to require bill-soaring heating or cooling, converting this liability into the 10-star rating.

How many stars should I aim for?

It all depends on how important energy efficiency is to you, balancing the possibility of reduced bills in the long-term with your up-front investment to find a middle ground that might be workable for your budget.

While Australia has yet to implement mandatory energy-efficient design in new builds, it’s something that may come into play in the future. It’s also worth noting that it’s much easier to achieve a higher score with smart planning on a Metricon new build than it is trying to retrofit many older homes.

If the idea of an energy-efficient home appeals to you, obviously a ten-out-of-ten NatHERS score is brilliant, meaning no costly heating or cooling is required, but the investment involved in building a home like that could come with a sky-high outlay that’s prohibitive for many home-buyers.

Anything six-plus is a great option.

If you decide the official NatHERS seal of approval isn’t right for you now, there are still plenty of energy-efficient ideas you can incorporate into your build that may save you money and increase your level of comfort. Check out some solutions here.

Metricon is here to help guide you through star ratings. Get in touch with an enquiry here, and sign up for our newsletters here.

*Queensland do not currently use NaTHERS for energy-related compliance.