Last Update: 12/05/25 Contact: admin@neversleep.com.au This site is still a work in progress...
I have a vast interest on the residential building designs and I am focusing on the National Construction Code (NCC 2022) Class 1A, 2, 4 and 10 to design energy efficient houses. I am currently a building designer (yes, I can draw up plans for submissions to the ACTPLA/council for approval), a Nationwide House Energy Rating Scheme (NatHERS) accredited assessor and hold an ACT building Assessor Class A licence. I can perform and generate Energy Efficiency Rating (EER) certificate nationally, however, I am currently only doing consulting/advice work.
So, where do you start?..do you engage an architect, a building designer, a draftsperson or an accredited NatHERS assessor first? My advice is to save your time and money, whatever your budget or complexity of your building is, look for an expert that can do both, that is someone can draw up your plans and also has a qualification as an accredited NatHERS assessor. Mostly, all of them can draw up your plans. You do not want to go back and forth with your revised plans between the architect/building designer and the accredited NatHERS assessor. You will pay more and waste a lot of time.
Architects, building designers and draftspersons will typically use of one of the two Building Information Modeling (BIM) tools, such as Graphisoft Archicad or Autodesk Revit ©. If they are also an accredited NatHERS assessor, they will need to use one of the four software (in step 2 below) to get the EER rating certificate generated equal to or above 7 stars as well.
How to build a residential house with more than 7 stars energy rating (EER)?
The following steps will guide through the process of building your house with more than 7 stars.
Design consideration is like a food recipe. If you have the correct food ingredients, you can cook up a storm and that storm is your perfect dish, therefore by having considered all the following steps in your design, you can be assured in acheiving a good EER rating.
Pre-work: House design consideration
When building a house, the following design condieration matters:
- Site Location: Where you will build? Whether it is in a hot tropic areas like Cairns or a cold weather areas like Canberra.
- Site Orientation: Where is the site facing? North, South, West-South etc... This will have an impact where you will put living areas in, bedrooms etc..
- House living area size: What is the total areas of the living areas?. This will have an impact if your living space area is too large etc. e.g. 300m2. The larger living areas of the house, the less air tightness, your overall EER rating will drop.
- External wall:Type of wall cladding e.g. Brick Veneer, Double Brick, Hebel Panel, Fibre Cement, Form etc...
- Window Glazing: Whether it is double or triple glazing with aluminum, timber or PVC framing etc.
- Floor: Under Slab Insulation, Slab Edge Insulation, Suspended Floor Insulation etc.
- Ceiling and Roof: Ceiling Insulation and Roof Insulation etc.
- Insulation: Type of insulation and their R ratings. For example, wall insulation is R2.5, ceiling is R6, roof will be Anticon reflective blanket of R1.3 etc...
- Shadowing: Eaves, Retaining walls, Shades, Trees, Fences, Neighbours 2nd floor buildings etc.
- HVAC system: Air flow inside the house, regular circulation of air movement etc.
- Solar panels and Batteries: Energy genration, storage and offsets etc.
Step 1: Read the NatHERS Technical note and understand the technical requirement
The current release of the NatHERS Technical note is version 20241023. You do not need to read all of the pdf pages. Only focus on some sections/criteria.
We will build a single story for an approximate 60m2 living space, you can change the size according to your need.
- Zone - Page 16: A minimum of 3 zones: Kitchen/living, a Bedroom and an unconditioned zone. e.g. Bathroom/toilet. Review Appendix 1: Zoning in NatHERS (page 43)
- Floor - Page 17-18: Waffle pods, Non-insulating void-forming constructions etc..
- Walls - Page20: Exterior and internal colour, insulation, earth materials etc..
- Windows and doors - Page 21-24: default windows, and glazed doors. Page 24 is a good reference to specify the windows openings.
- Ceiling and roofs - Page 25-26: Roof and ceiling colour, penerations and insulation.
- Shading: Page 26: Window shade, eaves and horizontal shading device, trees, fences and neighbour buildings etc..
- Appliances (Whole of Home): Page 33: Heating and cooling, Hot water systems, Solar panels and batteries etc..
Step 2: Choose a software to model on
Here you can download and use one of the 4 software to model your home. The 4 software are free to use for everyone, training is also free and provided and you can sample and generate the EER rating yourself to target the 10 stars by changing the R rating of the insulation values. You may need to read additional notes on the materials used and their R values.
- AccuRate is a software tool developed by CSIRO.
- BERSPRO is developed by Energy Inspection.
- FirstRate5 is developed by Sustainability Victoria.
- HERO is developed by Hero software.
You can always learn and perform your own assessment free of charge ($0.00). For example, by downloading one of the four software, register it as a non-accredited assessor. The EER rating generated by the software will give you the star rating as a guide only. Of course, if you pay the certificate as a non-accredited assessor, it will cost you between $40-$50 and you can see the sample generated certificate here. It is all black and white without any NatHERS logo.
If you get an accredited NatHERS assessor to generate the certificate, a sample is here. The certificate will cost the same as a non-accredited between $40-$50 plus NatHERS assessor fee depending on the complexity of your building anywhere between $500 and up.
NatHERS assessors are trained with a qualification in Cert IV in Home energy efficiency and sustainability, receive ongoing technical support, access to Continuing Professional Development (CPD) training and they must belong to one of the three accredited Assessor Accrediting Organisation (AAO) Design Matters, Home Energy Raters Association (HERA) or, Australian Building Sustainability Association (ABSA). They are also audited by the AAO for compliance and need to keep the assessed NatHERS certificates for 7 years (Data Retention on page 13 section 3.10 of the NatHERS Technical note).
How to model and build a 10 stars EER house
You start with a set of plans (site, floor, elevation and electrical) in the pdf format, these plans are usually generated from one of the BIM tools, once you have imported into one of the four software covered in step 2, you'd be able to scale these plans and ready to overlay to create zone in step 1, wall, window, door, openning, stairwell, void, shading screens, wing walls, ceiling fans, exhaust, downlights and penerations. You also need to enter the address and postcode (each postcode is allocated a 'principal climate zone' and sometimes one or two alternative climate zones) and orientation following the north arrow on the pdf site plan etc...
A good introduction YouTube video shows one of the four software, FirstRate 5 is here. You can follow Ricardo Muller's video (approx 44 minutes) to get a better feel of the software in action. Though, his energy rating was rated at 6.7 stars 3 years ago where 6 stars was the minimum standard.
More to come later!