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Tips On Getting A 6-Star NatHERS Assessment

Global warming and climate change are the two alarming environmental challenges faced globally. The construction sector contributes to the largest Greenhouse gas emissions. To combat the impact of buildings on the environment and promote a sustainable future, the Australian government introduced several energy and thermal efficiency standards for both residential and commercial building sectors. 

Sustainability standards for residential sectors include BASIX certification and NatHERS assessment. Section J report, JV3 modelling, and NABERS rating applicable for commercial buildings. 

Today’s blog will focus on what exactly is NatHERS star rating and How you can incorporate specific designs to improve your star rating. 

What Is NatHERS Star Rating?

Launched in 1993, The Nationwide House Energy Rating Scheme ( commonly known as NatHERS) is a sustainability measurement system that rates residential structures based on their thermal performance. 

The dwelling thermal and energy performance rating is generated by a NatHERS accredited software and needs to be undertaken by a NatHERS assessor. NatHERS assessment is by far the most attractive approach to obtaining residential sustainability compliance.

In 2010, the NCC increased the acceptable thermal efficiency baseline for residential development from 5 to 6 stars using a NatHERS-approved assessment software. Therefore, to attain sustainability compliance, building designs need to accomplish a minimum of 6-starts, 

So how do you attend a 6-star rating through net house assessment? 

 Let’s find out!

But before that, ensure that you are getting your BASIX, NatHERS, and BCA section J report prepared by a trained and accredited building professional. 

7 Design Tips To Achieve A 6-Star NatHERS Rating

Here are some practical design concepts to improve your NatHERS star rating. 

Reduce Overall Glazing By 2-3%

  • Increased glazing can result in huge energy holes leading to substantial heat loss during the colder season and heat gain during the summer months. 
  • In fact, glazing contributes to 40% heating energy loss and 87% heat gain within a residential structure. 

Reducing the glazed areas by as minimum as 2-3% retains the desired aesthetics while considerably enhancing the energy efficiency of your residential structure. 

Consider Glazing By Orientation

Glazing orientation can have a significant effect on your NatHERS star rating. In East and West facing windows, glazing can lead to complications in star rating due to extensive exposure to direct sunlight resulting in increased cooling loads. 

These effects are most evident in daytime-occupied climatic zones where a large proportion of energy consumption is contributed by enhanced cooling loads. 

  • However, glazing in north-facing Windows is actually beneficial. North-oriented glazing facilitates passive heating in temperate climatic zones leading to a reduction in heating loads during the winter months. 
  • Appropriate orientation-based glazing accompanied by proper shading can reduce direct sunlight exposure in hot and temperate climatic zones, thus, reducing significant cooling loads. 

A building consultant with significant experience in NatHERS assessment can suggest you orientation-related glazing designs to improve your star rating. 

Interior Zoning And Room Layout Designs

Interior room layout designs refer to the placement of rooms within a residential structure. Zoning and room layout designs substantially influence star rating, especially when combined with orientation. 

Additionally, interior zoning division into conditioned (provision for artificial heating and cooling appliances) and unconditioned ( washroom kitchens and wet areas generally not requiring artificial heating or cooling) areas can also impact the NatHERS star rating. 

Interior zoning and the space layout is also an important factor for achieving thermal comfort and Energy Efficiency within a commercial structure. Therefore, the proper layout should be considered during  BCA section J report preparation. 

You can follow a few design considerations for interior zoning and room layouts.

  • Ensure grouping of non-condition spaces, including kitchen, laundry area, and bathroom with external windows to improve energy efficiency and reduce insulation costs. 
  • Combine insulation of internal walls with non-conditioned spaces to reduce the requirements of external wall insulation within the residential structure. 
  • For hot and temperate climate zones, ensure designing daytime occupied spaces towards the south and nighttime occupied spaces in the northeast or west zone to achieve greater natural thermal comfort. 
  • The opposite design concept works best for colder climatic zones with north-facing Windows located in the daytime-occupied zones for attaining maximum passive heating. 
  • A sustainable residential structure aims to achieve both design aesthetics without compromising thermal and energy efficiency. 

Roof Colouring

Roof colouring can contribute to increasing a single-star NatHERS rating and improving your overall building thermal performance. 

  • For warmer and temperate zones, lighter roof colours such as white undertones, light pastels, etc., can enhance the thermal efficiency of your entire dwelling.  
  • Similarly, darker roof colours, such as shades of black, brown, dark grey, etc., in colder climatic zones contribute to reduced heating requirements. 

Hot temperate climate zones include Sydney, Brisbane, Darwin, and Perth, while colder climatic zones include Melbourne and Canberra. 

Shading

Introducing proper shading in your residential projects, such as eaves, shutters, plantings, and awnings can improve thermal comfort by allowing maximum sun exposure and passive heating during winter while blocking scorching heat rays and preventing heat loss during the summer. 

The most appropriate shading strategy will vary depending on the climate and house orientation.

Ventilation And Air Tightness

Ventilation and air tightness are also integral parts of the NatHERS assessment. 

Ventilating the interior of your residential structure and facilitating fresher circulation are essential for a healthy living condition. However, their circulation needs to be controlled rather than allowing uncontrolled air leaks and thermal variations. 

Ensuring proper sealing is one of the simplest ways to upgrade your NatHERS rating while increasing internal comfort and minimising operational energy costs. 

Consider The thermal mass of construction materials

Thermal mass is defined as the ability of construction or building material of construction or building material to absorb and store heat energy. Proper utilisation of thermal mass within your residential structure can considerably reduce your heating and cooling costs. 

Wrapping up

Thermal efficiency isn’t a new concept in the Australian building industry. But it is gaining substantial momentum as a critical element of sustainable building design. 

James Morkel

Tech website author with a passion for all things technology. Expert in various tech domains, including software, gadgets, artificial intelligence, and emerging technologies. Dedicated to simplifying complex topics and providing informative and engaging content to readers. Stay updated with the latest tech trends and industry news through their insightful articles.

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