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The change from 6 star to 7 star energy rating requirements

The change from 6 star to 7 star energy rating requirements

On May 1st, the new energy efficiency provisions under National Construction Code came into effect, introducing a new minimum standard for thermal comfort in residential homes. As a result, all new homes now need to adhere to a minimum of 7 stars out of 10 in the Nationwide House Energy Rating Scheme (NatHERS), a 25% increase on existing standards. 

So what does that mean for your new home and how we build it? 

What are the new standards?

The NatHERs energy rating system quantifies how well a property keeps its occupants hot or cold over the season – for example, a 0 rating does nothing to help you keep warm in winter, or cool in summer. The current minimum is a 6-star rating, which allows for a good, but not outstanding thermal performance. 

The National Construction Code changes dictate that all new homes now need to achieve a 7-star rating, helping to save money, reduce emissions and make significant in-roads in addressing climate change. The increase is expected to cut 72,000 tonnes of CO2 emissions a year in Victoria. 

How will my home reach 7 stars?

The NatHERS star rating is determined by a number of features, including layout, insulation, design, materials, orientation and aspect. 

The key to achieving this higher standard is considering sustainability from the very initial stages of design. Start with orientation, positioning your home to emphasise opportunities for passively heating the home in winter, while keeping it cool through shade in the summer. As a general rule, living areas should face north, as they tend to receive sun for the longest part of the day in winter, and can be easily shaded in summer. At RoomFour, we can advise on the best approach for your orientation, based on your block and location. 

Other initiatives include improved insulation in ceilings, walls or under the floors, and high-performance windows (otherwise known as double or triple glazing). Placing windows on opposite sides of your living spaces will encourage natural ventilation, and ceiling fans will reduce the reliance on mechanical ventilation, thereby reducing energy costs. It also goes without saying that energy-efficient appliances are also an effective way of satisfying the requirements.

Shading is a huge factor in sustainable homes – when you prevent direct sunlight from entering your home, you significantly reduce the potential for overheating, and hence a need for air-conditioning. Effective shading can block up to 90% of the intense summer heat through eaves, pergolas, external blinds and natural vegetation. 

What is it going to cost? 

Here’s the good news – not much! Many builders are already building 7-star homes, proving that these standards can be achieved in an affordable and accessible way. Analysis conducted for the NCC in 2021 found that the estimated additional cost of materials required for a four-bedroom house to meet the standard would be approximately $3310. 

When compared to the predicted savings from energy bills, this cost was quickly replaced by an ongoing saving of up to $300 a year. These savings could increase even further should you choose to go all-electric, or invest in solar panels. 

A report from the Climate Council found similar results – occupants living in a 7-Star, all-electric home could save an average of up to $450 a year on heating and cooling, when compared to the current 6 stars. 

Want to know more about the new 7-Star rating? Get in touch with the RoomFour team today!


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