Insulation: The Science Behind It

In our past blogs we’ve briefly mentioned here and there how insulation works – that is, it stops heat flow. This is a very oversimplified and brief explanation, however. That’s why our Melbourne insulation team thought it was about time that we go into a bit more depth with a technical blog concentrating on the science behind insulation and how heat travels. Hopefully, after reading this you’ll have a better and more comprehensive understanding of how insulation works in your home.

Understanding heat flow

Heat is a type of energy that cannot be created or destroyed. It will always naturally flow towards colder areas and not stop until the temperature is the same. It is essentially an all-consuming type of energy in that respect. There are three different ways that heat can flow.

Conduction is the name given to heat that travels through solids. This can be within a single object or between two separate ones. When you put a pot on a stove, then conduction occurs as the heat will spread around the pot, changing its temperature and allowing us to use it to cook.

If heat is travelling through fluids or gasses, however, it is known as convection. The easiest example of convection would be a heater in a closed space. The heater gives off hot air that slowly replaces the cooler air in the space.

As the hot air expands, it becomes less dense and rises – leaving room to be replaced by natural, cool air – and thus, the cycle repeats. The same logic applies to a warm room with air conditioning.

Radiation refers to infra-red thermal radiation that is transferred from a hot surface to a cold one via air or a vacuum – like space. Thermal energy is emitted by virtually every object – the amount of heat will vary depending on the object.

Because space is a vacuum, thermal radiation won’t heat up anything as it travels through it – until it comes in contact with an object such as a satellite. Thermal radiation is the only method of heat transfer that does not require matter to be effectual.


How does this work with insulation?

As heat travels and consumes cold air, effective insulation must be able to reduce heat flow. If insulation contains small air pockets, then airflow can be managed and minimised – meaning less hot air gets into your home.

This is how to reduce convection. When it comes to conduction, however, the insulation should have very few solid materials as well as discontinuous fibres. Since thermal radiation absorbs into the material of the surface, it means that the material will rise in temperature before emitting the absorbed energy.


Key terms to know

There are several terms, which are involved in rating not only the thermal value (R-value) but also the thermal transmittance (U-value) and thermal conductivity (K-value).

  • Thermal resistance – As we know, the R-value is used to measure a material’s capabilities when it comes to resisting heat transfer. R-value = thickness in metres/thermal conductivity.
  • Thermal Conductivity – The measure of a material’s ability to transmit heat and how much heat it allows to flow through it – measured in W/mK.
  • Thermal Transmittance – The U-value measures the rate that heat is lost through conductivity. It is measured in W/m2K. Essentially, the U-value is determined by finding the R-value of each layer that is included during the construction phase of insulation. These are then added together to determine the total resistance value.
  • Lambda value – Represented by the Greek letter, λ, the lambda value is another name for thermal conductivity. The term Lambda 90/90, for example, states that 90% of the results that the insulation will provide are within 90% of what its quoted value is.


Looking for Insulation in Melbourne?

Now that you understand a bit more of the technical side of insulation and heat flow – it’s time to select some effective insulation. Whether you’re retrofitting an older property or installing in a new one, Insulation Essentials have all your Melbourne insulation needs covered.

We provide a wide variety of insulation types in an array of R-values, such as our impressive Glasswool insulation product. We also provide fast deliveries and quality installation services to ensure your project stays on budget.

If you require some insulation in Melbourne, then please give us a call on 03 8339 7111. You can also contact us by filling out the enquiry form found on our website.