Insulation and glazing are very important when creating efficient buildings in Australia, and for a good reason. When used correctly, they can optimize the natural temperature and contribute to a higher energy star rating. However, there are many misconceptions about these concepts and their connection to the mandatory 7-star energy ratings in Australia. 

That is what we’ll address in this write-up by explaining what insulation and glazing are and how they contribute to the efficiency rating of your building. 

What is Insulation and Glazing?

Before we jump to explaining how insulation and glazing are calculated with a 7-star energy rating, let us first explain these building materials.

1. Insulation 

Insulation is a buffer that slows the transfer of heat and sound from one place to another. It is a material that prevents heat from escaping buildings in winter and stops it from entering buildings during warmer seasons. 

The nature of heat is that it moves from high-temperature spots to low-temperature spots until equilibrium between both spots is achieved. For example, if you do not have insulation in your building, the heat outside will move towards the cooler interior, making it hotter in summer.  

2. Glazing 

Double glazing means having windows with two glass panes with air or agron gas between them. The gap between the two panes of glass act as the insulating part of the windows, with a gap that usually falls between 12 and 16 mm. Glazing is one of the most important things you can do to improve your home’s energy rating and achieve 7 Stars. 

The Connection Between Insulation, Glazing, and 7-Star Energy Rating 

Many people hope that their building’s star rating will be high, but that is not always the case. Today, around 80% of Australian homes have a 2-star or even lower rating—a concerning number. 

Insulation and glazing values are considered a very important aspect, measured in R-value and U-value, respectively. The higher the R-value of insulation, the better. On the other hand, the lower the U-value of glazing, the better for efficiency. 

Here, it is important to note that if you are planning an open living area, high levels of glazing might not be beneficial. That is because you can only install a limited number of insulation batts. Glazing should always be applied after careful consideration: the recommended range for glazing-to-floor areas is 15-25%. 

The Role of Windows 

Windows play a critical role in your home’s overall efficiency scheme, as they allow natural light to heat the interior. However, this doesn’t mean you should install as many windows as possible.

A case can be made for installing as many as possible on the northern side, which will provide free heating and boost the energy rating. The problem is that this setting doesn’t work well on an overcast day or in the evening—in these situations, the R2.5 insulation batt is a much better choice. 

Insulation and External Cladding 

It is crucial to note that insulation is far cheaper than glazing, so the former should always be the first choice for meeting efficiency requirements. Insulation is done by filling the cavities based on their size: If the cavity size is suitable only for an R2.5 batt, you cannot use an R4.0 batt. 

Chat with your builder and energy rater , they will recommend a suitable range of insulation for each cavity and building component. Usually, they do not go beyond this level because it only offers very minor improvements in efficiency, but the cost escalates. FirstRate5 is one of the leading software choices for calculating the required R-value. The product is then selected based on its ability to meet the energy efficiency requirements. 

A Word of Caution Regarding R-Value: It is not a good idea to calculate the total R-value of materials, which accounts for the whole wall system and not the product itself. As a result, the value is much higher than that product can actually achieve. 

When it comes to external cladding, it is crucial to remember that external cladding has a low R-value. The highest R-value in this context can be achieved with EPS cladding (50mm–100mm), increasing the star rating by 0.1-0.2 stars.

Get Your Building Analyzed by PassivEnergy 

If you want to design a new building or upgrade an existing one, it is critical to follow the latest 7-star energy efficiency requirements. To achieve them, you need an industry-leading consultant like PassivEnergy, who has extensive experience in construction and sustainability. 

With a dedicated team that can do whole-of-home assessments, NatHERS experts, and ESD consultants, we guarantee a world-class service. Whether it is a 7-star energy rating assessment, Sustainable Design Assessment (SDA), Waste Management Plan, or more, PassivEnergy is always ready to take on these sustainability challenges.

So, contact us today and get your space assessed for a 7-star energy rating.