The Basics of Thermal Insulation

The basics of thermal insulation

Thermal Insulation is an important part of every house and helps keep your house warm in the winter and cool in the summer. To understand how thermal insulation actually works however we need to take a few steps back and take a look at some of the science around heat transfer.

What is heat transfer and how does it work?

The first thing to know about heat transfer is that heat will always try and move from the warmest areas to the coolest ones, seeking a balance. In the home, the greater the temperature difference, the faster heat will try and flow into the coldest area. Research tells us that the three methods of heat transfer are conduction, convection, and radiation. Let’s have a quick look at these.

Heat transfer through conduction

Conduction refers to heat transfer at the molecular level within a certain material. The material might be a solid, gas or liquid but heat transfer happens when there is a temperature difference between two materials, and they come into contact with one another.


Molecules are agitated when heat is conducted from one particle to another. The rate of heat transfer will increase or decrease depending on the difference in temperatures between the two materials, and the thermal conductivity of these materials.

Heat transfer through convection

When a fluid, such as air or a liquid is heated and travels away from its source, it carries the thermal energy with it. This type of heat transfer is called convection. The fluid above a hot surface expands, becoming less dense and it rises.


A good example of convection heat transfer is a hot air balloon. A hot air balloon rises because warmer air is less dense than cool air. Since the balloon is less dense than the air around it, it becomes positively buoyant and rises.

Heat transfer through radiation

The final heat transfer method is through radiation. In this example heat actually travels through light, either as infrared light or other types of electromagnetic waves. The energy is freely transferred through a direct line of sight or through translucent materials.


A great example of radiation heat transfer is simply looking at sunlight. As sunlight impacts a surface it starts to heat up. If you’ve ever stood barefoot on a sandy beach in the middle of a hot summer’s day you’ll know what I mean here.

Different materials act differently to radiation heat transfer which is why some surfaces get hotter than others in direct sunlight.

So I understand heat transfer, how does this impact my home’s thermal insulation?

Really only convection and radiation heat transfer directly impact the home. That’s why thermal insulation is mainly designed to combat these types of heat transfer.

Thermal insulation is a material with a high thermal resistance value. Thermal resistance levels are measured by an R-Value. The material creates a barrier to avoid heat transfer between the inside and outside of the home.

So to better understand how thermal insulation works, let’s look at two different scenarios.

Thermal insulation for radiation heat transfer

Let’s say you’re in the middle of summer and your home has no thermal insulation in the roof. Radiant heat from direct sunlight at the hottest time of the year will cause the home to heat up.

This radiant heat will quickly pass straight through the roof and walls heating the inside air of your home and creating an oven-like environment inside.

Adding thermal insulation to your roof and walls means would stop the radiant heat passing through these surfaces, preventing the house from heating up as quickly.

Thermal Insulation for convection heat transfer

Let’s say you’re in the middle of winter and again there’s no thermal insulation barrier in your roof or walls. Naturally, you’ll put a heater on to try and warm the room. Unfortunately, because of the large temperature difference, the heat will quickly escape from the house however it can make it incredibly difficult and costly to keep the house warm.

After adding a thermal insulation barrier, heat will no longer be able to escape the house. This means that the heater will be far more efficient at warming up the home. It also means the heat will remain inside for longer, resulting in a far more energy-efficient home.

Talk to an insulation expert about completing your home’s thermal barrier

If you’re interested in adding thermal insulation to your home it’s best to talk to an expert. Our team will be happy to provide a free assessment of your property and provide advice and direction on the best way to fully insulate your home. Once your thermal barrier is in place you’ll notice the difference instantly.

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