How Does Insulation Work?

These days, most people understand that insulation is an important component of any home or commercial building. But how does insulation work? Briefly explained, thermal insulation is made of materials (such as glass wool or polyester) that are good at slowing down the transfer of heat.

In this article, we'll explain what insulation does and the science of how it works. There are many different types of insulation products and understanding how they work can help you choose the best product for your needs.

Does Insulation Help With Heat?

You might have heard that insulation helps keep the warm air inside your home during winter, but what about summer? Does insulation help when there is a high temperature outside? It sure does.

A material that is a good insulator works both ways. Whether the heat is on the outside or the inside of your home, insulation acts as a barrier to the flow of heat. That means heat can't escape as fast during winter and it can't creep into your home as fast during summer.

What Does Insulation Do?

When insulation is installed in the roof, internal and external walls and under floors, it helps regulate temperatures inside your home so that you can stay cooler in summer and warmer in winter. If you've noticed that your home heats up quickly on a hot day or is freezing cold on a winter's day, it could be time to install insulation or upgrade your existing insulation to help you regulate temperatures better.

Understanding Heat Flow

To understand how insulation manages to keep pleasant temperatures inside your home, you first need to understand heat flow.

Heat is thermal energy. It always flows from areas of high thermal energy (hot areas) to areas of low thermal energy (cooler areas) until both areas are equal. So if it’s hot outside, and cooler inside your house, that thermal energy will tend to flow into your house. The same is true if your home is nice and warm and it is cold outside: the heat inside your home will flow outside.

Heat – or thermal energy – can flow via radiation, convection or conduction. Simply explained:

• Radiation is energy that travels in a straight line from a source such as the sun.
• Convection is how heat travels through liquids and gases.
• Conduction is how heat travels through a material between particles.

To prevent warmth escaping from your home in winter, or heat flooding your home in summer, you will need something to resist or restrict heat flow. That’s exactly what insulation does.

How Does Insulation Work?

Insulation materials predominantly help resist radiation and conduction of thermal energy. Below we explain how two main types of home insulation – reflective and bulk insulation – resist heat transfer.

Reflective insulation acts as a radiant barrier. It has a thin foil layer on one side. Installing reflective insulation in the roof with the foil layer facing down will help reflect thermal radiation from the sun away from your home.

Bulk insulation works by trapping millions of tiny air pockets which break up the path of heat flow and slow down the conduction of heat into or out of your home. Bulk insulation is commonly made from glasswool (fibreglass insulation) or polyester.

It is critical that bulk insulation is not compressed during installation as this will reduce the number of air pockets and make the insulation less effective. Insulation products with a higher R-value have more air pockets, making them more effective at resisting the conduction of thermal energy than those with a lower R-value.

What Is The R-value Of Insulation?

In Australia, every insulation product is given an R-Value. New homes are required to meet certain R-Value standards, depending on where they are built. R-Value is the measure of thermal resistance. Or in other words, the higher the R-Value, the better the insulating material is at resisting the transfer of heat energy. Installing higher R-Values will help you keep the indoors at a comfortable temperature all year round.

The table below shows our recommended R-Values based on region and where the insulation is being installed. Note, the greatest heat loss and gain occurs in the ceiling. That's why this area of the home needs a higher R-Value. If your budget allows, upgrading to a higher R-Value will improve the comfort and energy efficiency of your home.

Location	Min. R-Value for Ceiling	Min. R-Value for Walls	Min. R-Value for Floors
Sydney, Melbourne, Adelaide	R5.0 or R6.0	R2.5	R2.5
Perth, Brisbane, Northern NSW	R4.0	R2.0	R2.0

For more information, read our guide "What Does R-Value Mean?".

Installing Thermal Insulation Saves Energy

If high-quality insulation is installed correctly in a home, it will inevitably lead to energy savings. That's because insulation resists and restricts heat flow, keeping the inside of your home at a more pleasant temperature and reducing the need to use your air conditioner or heater.

For the majority of Australian households, heating and cooling are two of the largest contributors to their power bill. Installing insulation could help reduce these costs significantly.

When you do put the air conditioning on, insulation will help make your cooling more energy efficient. Your air conditioner won't have to work as hard and the same is true for your heater in winter. Insulation will not only help you save on energy bills, but by reducing your energy consumption, it is one of the best things you can do to make your home more environmentally friendly.

How Does Acoustic Insulation Work?

In this article, we have been focussing on thermal insulation and how it resists heat gain and loss. Another type of insulation commonly used in Australian homes is acoustic insulation. Like thermal insulation, it helps reduce heat transfer while also reducing the transmission of sound between rooms and from outside.

When sound waves hit a surface, they are either:

• transmitted through the material to the other side
• reflected by the surface and bounced back into the room
• absorbed by the material

Acoustic insulation is specially manufactured to absorb sound waves and is more dense than thermal insulation. It is most commonly installed in the internal and walls and between floors of a multi-storey home to stop sound being transmitted between rooms and floor levels in the home.

For more information, check out our guide "What is sound insulation and how does it work?"

Choosing The Right Insulation For Your Home

Whether you are looking for roof insulation, underfloor insulation or acoustic wall insulation, choosing the right product for your project is important.

If you are planning a DIY installation, we have many informative articles and guides to help you get the best result. Check out our guide on how to install ceiling insulation or watch our DIY insulation videos.

At Pricewise Insulation, we have a wide range of thermal and acoustic insulation options from the most reputed brands in Australia. Buy insulation online today or call us on 1300 729 639 to place an order.