
When constructing our homes, it’s easy to overlook the importance of insulation in reducing ongoing energy costs. Insulation represents less than 1% of the total construction cost, yet heating and cooling can account for around 39% of energy use in your home.
Investing in the right insulation can slow the rate at which heat enters and exits your home, stabilising internal temperatures, reducing heating and cooling requirements, and improving your comfort.
How Does Heat Transfer Work?
Heat transfer doesn’t discriminate—it seeks to equalise temperatures across different materials. For instance, when you leave a hot cup of coffee on your desk, the heat radiates out through the cup and eventually reaches room temperature. This process is the basis of heat transfer. Good insulation resists this transfer, helping maintain a stable indoor climate.
A fun fact: Insulating around your bathtub helps keep your bathwater warmer for longer, as it increases resistance to heat transfer.
What Is R-Value and Why Is It Important?
Insulation effectiveness is measured by its R-value, which indicates the material’s resistance to heat transfer. The higher the R-value, the more effective the insulation is at reducing heat movement.
In Australia, building standards require a minimum R-value of R2.5 for walls and R4 for ceilings in new builds across Victoria. Prior to 2004, homes were not required to be insulated, which often kept construction costs low at the expense of energy efficiency.
Common Insulation Materials
Several materials are used in insulation, each with varying degrees of effectiveness. Good insulators include foil, glasswool, polyester, cellulose, and even air. Poor insulators like glass, metal, earth, and concrete increase heat transfer rather than resist it.
Maximising Energy Efficiency
As this diagram from Sustainability Victoria demonstrates, significant improvements in energy efficiency can be achieved by insulating ceilings, walls, and underfloors, as well as draught-proofing your home. These strategies help to resist heat transfer, making your home more comfortable and energy-efficient.

Choosing the Right Insulation
When purchasing insulation, consider that the higher the R-value, the better the material will resist heat transfer. It’s worth investing in reputable brands, quality installation, and as high an R-value as is practical for your home to maximise comfort and reduce energy consumption.
For more information on how insulation can improve your home’s energy efficiency, check out our Insulation pages:
Investing in the right insulation will not only increase your comfort but also lower your energy bills over time.