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Whole of Home Assessment

The NatHERS Whole of Home rating measures the energy use of the whole home including appliances, solar and batteries. NatHERS Whole of Home ratings provide an easy-to-use rating to show how the home meets or exceeds the new NCC annual energy use budget which requires consideration of the efficiency of the appliances used in new homes as well as solar and batteries.

In this article, we provide important information regarding the recently introduced Whole of Home assessment which coincide with the updated NCC 2022 residential energy efficiency standards.

What is a Whole of Home Assessment Rating?

NCC 7 stars

The recently released NCC 2022 energy efficiency standards for new residential developments include the introduction of a Whole of Home rating to measure the energy use of the home.

In simple terms, the rating considers the energy used in a household for heating, cooling, appliances and equipment, minus any energy generated from solar panels.

Whole of Home assessments aim to lower energy costs by helping homeowners make cost-effective choices about their home’s appliances and equipment.

Homeowners, designers and builders can explore the trade-offs and benefits of different technologies, appliance efficiencies and thermal performance to create a home and appliance design that works for them and their budget.

A Whole of Home assessment involves the following appliances and equipment:

  • Lighting
  • Heating and cooling
  • Hot water
  • Swimming pool and spa pumps
  • Cooking and plug-in appliances.

 

Onsite energy generation and storage (e.g. solar PV and batteries) can also form part of a Whole of Home assessment where these are included in the design documentation.

The Whole of Home rating scale ranges from 0 to 100 – whereby, a poor energy performing home would rate under 40, while a score of 100 is a net zero energy value home. A rating over 100 is possible where the home is producing more energy than it uses. Ratings at 100 or above mean the home will have low or no energy bills.

The new NCC 2022 residential energy efficiency standards mean new houses and townhouses will need to achieve a minimum Whole of Home rating of 60 (out of 100) and new units a rating of 50 (out of 100).

Numerous appliance combinations can be utilised to attain a high Whole of Home rating. Efficient water heating systems and properly sized space heating or cooling systems not only save money but also guarantee a comfortable and resilient home in varying climates. Additionally, on-site renewable energy generation can assist in offsetting the home’s energy consumption.

Learn more about buying energy efficient appliances.

"The relationship between a home’s thermal performance rating and its Whole of Home rating means that increasing thermal performance will increase the Whole of Home rating."

Thermal Performance

Thermal Performance simply put, is a factor that is concerned with how well a home retains heat. This can be the defining factor between a freezing cold home in the winter or a warm and cosy one.

The relationship between a home’s thermal performance rating and its Whole of Home rating means that increasing thermal performance will increase the Whole of Home rating. This is because the heating and cooling energy needs will be lower in a home with a higher thermal performance rating.

Did you Know?

A flawed design could result in very cold or hot living spaces, as well as condensation on walls, paint deterioration, potential mould, extreme discomfort and possible ill health?  Energy efficiency and passive design techniques are crucial elements for creating a home that is not only sustainable, but both functional and healthy to live in. 

Existing Homes

The Australian Government and state and territory governments are working together to develop energy performance assessments for existing homes. 

  • Work is underway to expand the Nationwide House Energy Rating Scheme (NatHERS) to include existing homes, with ratings to be available from mid 2025.
  • Residential Efficiency Scorecard assessments, which offer an alternative way of assessing the energy performance of an existing home, are available now.
  • The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is developing RapidRate, an artificial intelligence powered tool for quickly estimating the energy ratings of homes using fewer inputs.

 

Stay tuned for more information!

In Summary

The recently released NCC 2022 energy efficiency standards for new residential developments introduces a ‘Whole of Home’ rating to assess a household’s energy use, excluding solar energy.

The rating helps lower energy costs by guiding cost-effective choices for appliances and equipment, allowing homeowners to optimise technology and thermal performance within their budget.

A Whole of Home Assessment is mandatory for new residential developments in all states except NSW which utilises the BASIX method of compliance.

Contact the team at Stellar Thermal today for more information regarding Whole of Home Assessments.