WHAT ENERGY EFFICIENCY REPORT DO I NEED FOR MY HOME?
Not sure which Energy Efficiency assessment method to use?
Didn’t even know there were different asesssment methods?
Our simple guide here will help you understand the options, and decide which one is best for your buiding project.
Energy Efficiency assessment options can sometimes feel confusing, and many people aren’t 100% sure exactly what kind of report they need.
The National Construction Code (NCC) helpfully provides a range of Energy Efficiency assessment methods, recognising that different projects have different features that may be suited to one method or another. Each assessment method produces a different kind of report. It’s important to note they are all valid under the legislation; any one of them can be used to demonstrate Section J Energy Efficiency compliance.
The decision about which method to use is usually made between the Architect/Designer, the Project Owner and the Energy Efficiency assessor. Factors that affect that decision are usually to do with the building design itself, something your Energy Efficiency assessor can advise you on.
There are three main assessment methods for Residential buildings:
- The “Deemed To Satisfy” (DTS) method
This is the basic assessment method used for simple residential buildings. It compares the Energy Efficiency elements of the building design to a series of benchmark requirements (as listed in the National Construction Code). It assess the main elements of the building shell, including Roof/Ceiling, Walls, Glazing, Floors, Ventilation and attached garages. If a building meets or exceeds these minimum requirements, it is ‘deemed to satisfy’ the NCC Energy Efficiency performance requirement.
The DTS method is the simplest and cheapest assessment method for Energy Efficiency compliance. However, people often find the DTS requirements restrictive, and use the next, more flexible option – NatHERS.
2. NatHERS Assessments
NatHERS ratings are produced using the National House Energy Rating Software (designed by CSIRO) which takes into account all the relevant design factors of the proposed house/apartment (including glazing, orientation, exposure, construction materials, insulation, size, eaves and much more).
The software, very cleverly, calculates:
-
- How much energy you’ll need to keep warm in the winter (the ‘heating load’)
- How much energy you’ll need to stay cool in the summer (the ‘cooling load’)
- Your home’s total energy use and a Star Rating to show how efficient it is
The National Construction Code specifies certain standards for each of these that each home has to meet to show it is compliant with the NCC Performance Requirement. From 2023, some states require homes to acheive 7 stars – but the requirements vary from state to state.
The NatHERS software option provides a lot more flexibility than the DTS option, and is a great option if your home has unusual features, if you’d like to get away from the DTS restrictions, or if you’d really like to understand the detail of the thermal performance of your home.
3. BASIX
Assessments for new homes in NSW must be done under BASIX requirements rather than NCC requirements. BASIX assessments incorporate water efficiency and appliance efficiency, in addition to thermal performance. Within BASIX, two methods for thermal performance are allowed: DIY (Similar to DTS above), and NatHERS.
What about “Whole of Home” assessments?
Prior to 2023 (NCC 2022 legislation), options 1 and 2 above focussed solely on the construction elements of a building (walls, windows, roofs etc.). From 2023, they must also include calculations for energy use from major appliances (hot water system, air conditioning and pool heater), lighting and so on. This ‘Whole of Home’ requirement can be calculated under either of the options above (DTS or NatHERS). This requirement is new, and has not yet been adopted by every state in Australia, so check out the ABCB website to see if it’s applicable to your home, or contact us for more info.
BASIX will continue to assess water and energy use of the proposed dwelling.
There are other assessment methods available (Verification using a reference building, Verification of building envelope sealing, Performance Solution), but these are used less commonly. BERA will advise if we believe one of these methods will be most suitable for your project.
Frequently Asked Questions
Does my home need to rate at 7 stars?
From October 2023, if your home is being built in NSW or the ACT, it will need to meet the 7.0 Star requirement (in NSW, via BASIX). Queensland is likely to adopt the same requirement on the 1st October 2023. While it’s a big jump from previous requirements, it can be achieved. We can assist with guidance on how to get to 7 stars without completely blowing the budget!
When is the 7 stars requirement for residential buildings being adopted in my state?
- NSW is requiring 7.0 Stars (via BASIX) from 1st October 2023.
- The ACT has confirmed that the 7.0 Star requirement applies from the same date.
- Queensland have proposed adopting the requirement from 1st October 2023, which looks likely to happen.
- Other states have deferred the adoption date for the requirement, to 2024 or beyond.
Adoption dates and policies have changed considerably, and may continue changing from those shown above (current August 2023). For the most up to date information, consult the ABCB adoption timetable.
Still got questions?
Get in touch – we’re here to help!