NatHERS Whole of Home Assessment

What is a NatHERS Whole of Home Assessment?

 

What are the requirements, what does it cost and how you can comply.

 

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What is NatHERS Whole of Home (WoH)?

The NatHERS scheme (6.0 stars) has been expanded to include a ‘Whole of Home’ rating. For most states and territories this comes into effect from May 1st 2024. It represents one of the biggest updates to the NatHERS Scheme in history.

 

Whole of Home will help support improvements to energy efficiency and the transition towards net zero carbon emissions.

 

The rating will show how the home meets or exceeds the annual energy use budget. The scheme aims to reduce energy usage through more energy efficient appliances and the use of solar panels to offset energy usage.

 

 

 

When is a Whole of Home Assessment Required?

Each state and territory has it’s own transition date as specified by the governments. The new “Housing Energy Efficiency” requirements under NCC2022 requires you to meet a NatHERS 7.0 star rating and a 60 point Whole of Home rating. This comes into effect on the following dates:

 

  • Australian Capital Territory: 1st January 2024
  • New South Wales: Whole of Home does not apply. You must comply with the BASIX requirements for NSW.
  • Northern Territory: NCC2022 housing energy requirements not adopted and still only requires 5.0 stars.
  • Queensland: 1st May 2024
  • South Australia: 1st October 2024
  • Tasmania: NCC2022 housing energy requirements not adopted.
  • Victoria: 1st May 2024
  • Western Australia: 1st May 2025

A Whole of Home assessment is only required for new dwellings. Renovations and alterations do not require a Whole of Home assessment and often do not require a 7.0 star NatHERS rating. Please contact us if you if you need an energy report for a renovation or alteration.

Whole of Home Requirements

The new ‘Whole of Home’ rating assigns your project a score out of 100. This score is based on the types of appliances you use, appliance efficiency and the use of solar panels.

  • Heating and cooling systems
  • Hot water system
  • Cooking appliances
  • Lighting and plug-in appliances
  • Solar energy and battery storage

The Whole of Home rating is required, in addition to a 7.0 Star NatHERS Rating (thermal comfort).

 

Household plug-in appliances selections do not currently impact the rating.

Heating and Cooling

Whole of Home considers the HVAC Type, the star rating of the system and which rooms are conditioned. This is an important part of the rating because the heating and cooling system accounts for around 40% of your energy usage.

HVAC Types

  • None/Unknown (Software will default to AC)
  • Room Air-Conditioner
  • Ducted Gas
  • Wood
  • Ducted Air-Conditioner
  • Room Electric Resistance
  • Room Gas
  • Evaporative

The energy rating of your system will impact your home rating. The rating will typically be on the label and is shown in (kW). It may vary depending on your climate and whether the rating is for the heating or cooling. If you are unsure of your rating, we can find this out for you using the model number of your appliance.

Hot Water System

The type of Hot Water System and the star rating of the system will impact your rating.

Hot Water System Types

  • Electric Storage (Peak)
  • Electric Storage (Off-Peak)
  • Electrical Instantaneous
  • Gas Instantaneous
  • Gas Storage
  • Heat Pump (Off-Peak)
  • Heat Pump (Peak)
  • Solar Electric Boost (Off-Peak)
  • Solar Electric Boost (Peak)
  • Solar Gas Boost
  • Wood

Cooking

Whole of Home considers the type of cook top and oven you are using.

Cooktop Type

  • Electric
  • Induction
  • Gas
  • LPG

Oven Type

  • Electric
  • Gas
  • LPG

Lighting

The power density of your lighting will impact the whole of home rating you achieve. The rating will assume a power density of 5W/m².

 

Did you know, if you use more energy efficient lighting you can improve your rating?

 

You can nominate 4W/m² or 3W/m² to improve the rating.

Pool and Spa

Whole of Home considers whether you have a pool or a spa. It will consider the volume, type of pump and the rating of the pump.

Pump Type

  • Single Speed
  • Dual Speed
  • Variable Speed

Solar & Batteries

Solar panels and batteries will improve your rating.

Information required for solar panels

  • Array Capacity
  • Inverter Capacity
  • Where the panels will be positioned on the roof

If you have multiple sizes of arrays or inverters this will included in the calculations. The software will automatically determine the time-period and exposure to the sun depending on the orientation and climate.

Types of batteries

  • Lithium Ion
  • Lead Acid
  • Zinc Bromine

Contact a Whole of Home Consultant

Get in contact today and learn how we can help you meet the Whole of Home requirements

Complying with Whole of Home

What rating do I need to achieve?

All new builds must achieve a minimum Whole of Home rating of 60 out of 100. Your appliance selections and the inclusion of solar panels or batteries will determine what rating you achieve.

How can I improve my rating to meet the minimum score of 60?

The most important appliances are heating/cooling systems and the hot water system. Your heating and cooling system accounts for around 40% of your annual energy usage. Your hot water system accounts for around 23% of your annual energy usage.

The following may improve your rating:

  • Nominating Air-sourced heat pumps/air conditioners
  • Selecting Gas appliances
  • Adding a solar PV system, or increasing the size of your system
  • Adding a battery
  • Achieving a NatHERS rating higher than 7.0 stars to reduce energy usage

 

Household plug-in appliances selections do not currently impact the rating.

Does the NatHERS Star Rating change my requirements?

The NatHERS Star rating you achieve will impact your Whole of Home rating. For compliance, you will require a minimum rating of 7.0 stars.

If you achieve a rating higher than 7.0 stars, your home will use less energy for heating and cooling. This will improve your Whole of Home rating. You can improve your star rating by using better glazing, higher performing insulation or improving the design of your home for energy efficiency.

 

You can learn more about the NatHERS Star Rating here.

Do I still need a 7.0 star NatHERS Rating if I get a higher Whole of Home rating?

The new Whole of Home rating is an extension of the existing NatHERS system.

 

To comply with NCC2022 using NatHERS, you must achieve a NatHERS rating of 7.0 stars, and Whole of Home rating of 60 out of 100.

What does it mean to achieve a home rating of 100 or above?

A score of 100 means that your home is considered to be net-zero energy value home. A rating above 100 is possible, and means your home is generating more energy than it uses.

What is the difference between Whole of Home and 7.0 stars?

The Whole of Home rating is focused on your appliances and renewable energy.

 

The NatHERS Star Rating is focused on reducing energy usage for heating and cooling by reducing how often you need to use heating and cooling systems. This means ensuring the home stays comfortable without needing to always use the heater or air-conditioner.

 

Click here to learn about the NatHERS Star Rating

Whole of Home Assessment Cost

The cost of a Whole of Home assessment will vary between $250 – $650 (plus GST). The cost is inclusive of a 7.0 star NatHERS Certificate which is also required as part of the assessment.

 

The price varies depending on the complexity and size of the project. Please contact us to organise a quote for your project.

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