Understanding Heat Transfer

When constructing our homes, we don’t construct to minimise our ongoing energy expenses. Insulation is less than 1% of the total construction cost yet heating and cooling accounts for on average 39% of energy use in your home.

Investing in the correct insulation will slow the rate at which heat enters and exits your home, stabilising internal temperatures, reducing heating and cooling requirements and costs whilst improving your comfort.

How does heat transfer work? Heat doesn’t discriminate, it wants everything to be the same temperature and will move and radiate to create a stable temperature. For example if you leave a hot cup of coffee on your desk, the heat will radiate out through the cup and will eventually become the same temperature as the air. Good insulation provides a resistance to that transfer.

A fun fact is if you insulate around your bath tub your bath water will stay a lot warmer for longer as there’s an increased resistance to the heat transfer.

Insulation effectiveness is measured by the R value. The R value shows how much resistance the product presents to heat transfer. Australian standards for new builds in Victoria require R2.5 for walls and R4 for ceilings as a minimum. Prior to 2004 homes were not required to be insulated, and in keeping construction costs low

Good insulators include foil, glasswool, polyester, cellulose and air. Poor insulators increase transference rather than resist it and include glass, metal, earth and concrete.

As this diagram from Sustainability Victoria shows great gains in energy efficiency and resisting heat transfer can be made by insulating your ceilings, walls and underfloors, and draught proofing your home.

When purchasing insulation consider the more the resistance the higher the R value and the better the insulator, it is worth investing in a reputable brand, a quality install and as high an R value as practical to maximise your comfort gain and reduce your energy consumption.