If you’re renovating or extending a house in Canberra, you will have to meet the energy efficiency provisions of the building code. These are outlined in the Building Act (ACT Appendix to the building code Determination 2012), and have not changed significantly with NCC 2022.
You will need to submit proof that you have met these requirements when you apply for your building approval, and they are specific to Canberra. There are three pathways we use, but by far the most common are either an energy efficiency rating and the glazing calculator.
Although we understand that the ACT Government will not be requiring existing homes to reach 7 stars (as required by NCC 2022 energy efficiency provisions from 1 October 2023), we are waiting for more information on how this will work in practice, and will update this article when we know more.
Do you need an energy efficiency rating?
All houses with extensions or renovations need compliance with the energy efficiency provisions. Generally, you’ll know you need an energy efficiency rating (EER) because your building surveyor will ask for one when you’re getting your building approval. There are two main pathways: an energy efficiency rating and a “deemed to satisfy” or glazing calculator. Rarely, we will use an alternative solution.
Although it is only required when getting your building approval, we would always recommend getting energy efficiency advice early in your project to ensure that your renovations will make your house more comfortable, not less!
The 3 pathways for energy efficiency compliance
Pathway 1: Full or partial energy efficiency rating achieving a minimum of 6-stars
The most common solution is an energy efficiency rating for ACT houses. An energy efficiency rating gives the designer and homeowner flexibility in addressing which parts of the house will be upgraded to meet the 6 star minimum. We’ll always consider cost-effective option to get 6 stars first: insulation. Secondly, we’ll look at the orientation of the windows, as well as the quality of the window frames and glass.
To create your home’s energy efficiency rating, we create a thermal model of the house. The model simulates the amount of heating and cooling it will need – the star ratings are based on the amount of heating and cooling your home will need per square metre. With renovations, our thermal models only need to consider the areas of the house being altered or added to, include the main living and kitchen areas, and have a minimum of 100sqm of floor – this is what we call a partial energy efficiency rating. We’ll consider if including areas of your home will be beneficial or not, before including them in your rating. We’ll also apply any relevant concessions available for older houses. This gives us some flexibility with meeting the 6-star requirement.
In our experience, a partial energy efficiency rating is the most cost-effective pathway for most extensions. Why? Because it looks at all the building elements – walls, roof, floors – not just the windows (see pathway 2 below). If there are any challenges, we can usually get to 6 stars by increasing the performance of your house through added insulation and design tweaks.
Note: Renovations and extensions only need to meet a minimum of 6 stars, whereas new builds have to meet a minimum of 7 stars from 1 October 2023 under the NCC 2022.
Pathway 2: Deemed to satisfy, also known as the glazing calculator
Using this method, we do calculations based on the windows (or glazing) in the house. Although this method is the fastest and cheapest, it can be difficult to comply with unless the work meets these very specific rules:
- The addition is less than 50sqm
- There is no opportunity for northern glazing
In these instances, we can use the pre-2009 glazing calculator to achieve a good outcome. This method is frequently used by builders, architects and building professionals in-house, as it is fairly straightforward to complete. If you are interested in improving the thermal performance or energy use of your home, this won’t help you – you’ll be better off engaging a professional thermal performance consultant for advice on how to make your renovation more energy efficient.
We will always advise clients if we think this pathway is appropriate for their build.
Pathway 3: Alternative solutions if intentions are good
An alternative solution is generally an expert report that provides a case for passing the proposed building.
The only time we use an alternative solution is when the renovation includes something not covered by legislation, such as a sunroom. In this case, we’re looking at whether the work aligns with the intentions of the code. An alternative solution still needs to be accepted by your building certifier, so we engage them as part of the process to make sure that they’re happy with the proposed solution.
More than an energy efficiency rating, look at these three things
When we help people make their renovations more energy efficient, we work through the house in three sections:
- Improve the building envelope. This means looking at the walls, roof and floor to ensure they are working for the house – insulation and airtightness will be your best bang-for-buck. (Check out our guide on how to insulate a timber floor, and the basics of airtightness).
- Get the best from your windows. Can you get sun in during winter? Can you shade the home during summer? Will you improve the windows with blinds and pelmets, or can your client afford high performance windows, like uPVC double-glazing?
- Don’t forget your systems. Finally, don’t forget the heating and cooling systems. Fixing the house as per point 1 will make your heating and cooling much more effective. We also recommend replacing any gas appliances with electric during a renovation, or planning power for the electric replacement if you are waiting for the end of an appliance’s serviceable life. Will you have solar? Do you need to wire in an electric car charger? Make provisions for these so your house runs well with minimal energy and is future-ready.
If you want to make the most of the energy efficiency process, request a quote to find out more about how we can help you prioritise your renovation actions with our Australian first, real-time home energy efficiency design app. We love helping people get the most comfort from their renovation!
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Featured image: Austin Maynard Architects renovation. Source: AFR.
