October 13, 2021

PART ONE OF THREE: What the heck is an Energy Rating?

In this three part series, founder and director of PassivEnergy, Rob Iacono demystifies the questions surrounding energy ratings, sustainable home building and his tips of what to consider when chatting with your builder. Today, Rob will get to the crux of what the heck an energy rating is, and why it is such an important aspect to the design of your home.

Quite often I am asked what I do for a living, and when I tell people one of the services we provide is 6-star energy rating reports, I’m often met with a blank face and a raised eyebrow.

If you have been to an appliance store selling white goods and electronics, you will more than likely see a label displayed on the corner of the product showing a few stars. Some products will display an electricity-guzzling 1 or 2 stars, while others may have 5 stars, but the intention of this labelling is to illustrate to the consumer how much power is used to operate the product and provides a direct energy comparison between products and brands.

With this in mind, we can relate a similar concept to the way in which energy ratings are applied to home designs. Let’s break it down simply by discussing the way in which Australian practice has changed over time.

Through the decades, Australia had been building homes and energy efficiency wasn’t really something that was thought about in great depth. This meant that the only thing separating us from the outside weather was some plasterboard, timber stud walls and some form of external cladding like brick or weatherboard. So, if you are wondering why your home might feel a bit like the Arctic during the colder months, or a sauna when we get consecutive 30 degree days, it is because the way we used to build offered little weather protection, which also ultimately leads to expensive power bills.

Hence, our trusty government officials came together and created the Nation-wide House Energy Rating Scheme (NatHERS). To cut a long story short, this was the inception of a star rating system which uses a numerical value between 1 and 10 to estimate how much energy the dwelling will use to keep it warm in winter and cool in summer. Most dwellings pre 2000’s average 1.5 stars (think deep freezer or volcano!). A 10 star home theoretically needs no heating or cooling devices to keep it comfortable all year round – wouldn’t we all love that?

In May 2011, a mandatory 6-star energy rating was required before any building permits were issued. Now, the reason I use the words ‘estimated’ and ‘theoretical’ in my discussions is because unlike white goods or electronics that go through thousands of hours of R&D and testing to work out their actual performance and energy consumptions, dwellings have a 6-star energy rating issued prior to the start of construction. In an ideal world, with a competent builder who checks to ensure insulation has been installed correctly and windows have been chosen to match what is stated in the energy rating report, you could indeed live in a comfortable 6-star home.

According to a report issued by the Department of Environment, Water, Heritage and Arts, heating and cooling accounts for 40% of the overall energy use in our homes on average within Australia. What the 6-star energy rating aims to achieve is better methods of keeping the warmth inside during winter, and keeping it out in summer, in hope that this will help to reduce the reliance on the amount of energy required to achieve a comfortable home.

What the 6-star energy requirement also aims to achieve is better thought in the design process to better utilise solar passive design principles, a method termed by using that beautiful warm winter sun that sits low enough in the sky so that it can penetrate through those north facing living areas where you spend most of your time – you don’t pay for the sun – that’s free energy!

The main points I’d like for you to take away from this are as follows:

  • The energy rating system is a relatively new concept within Australia but is ever increasing in importance due to the mandatory requirement of a minimum 6 star rating for any dwelling.
  • Make sure that you design intelligently with a knowledgeable builder in order to accommodate external factors for maximum energy efficiency.
  • You could be saving yourself A LOT of money – not applying these principles is akin to throwing your money down the drain!

The NCC 2022 will likely see the introduction of a mandatory 7 star rating accompanied by a whole of house scorecard system which will include appliances, lighting and swimming pools

Have more questions? If you’d like to work with me then get in touch today, let’s get you started on the right path!

READ PART TWO HERE – 10 must-haves to build a more sustainable home

Rob Iacono is the founder of Passivenergy, he has a background in architectural building design and sustainable design and is passionate about educating his clients on the importance of energy efficient homes and passive design principles.

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Efficient, cost effective sustainability (ESD) reports for building and planning permits.