What is Insulation, Why Do We Have it and How Does it Work?

A small science lesson about insulation:

Heat moves from warmer areas to colder areas. This is the single basic principle on which the idea of insulation is based. On hot days heat tries to get inside your house and on cold days the heat tries to escape. Insulation seeks to minimise this ebb and flow of temperature by slowing the process.

Unfortunately no matter how good your home insulation is, any building always needs a constant supply from a heat generating source to maintain a steady temperature. Of course however, if you have good insulation then you will need much less heat and thus a lot less energy to achieve the same effect.

Most of us learned in GCSE science about conduction convection and radiation.

Here is a brief summary of each to refresh every ones memory.


This is the process that heat flows through or along one material and into another. This is done through molecular transportation. To do this, the materials must be in contact with each other. This conduction happens with all things of liquid, solid or gas substances but that rate at which it happens greatly varies depending on the substance and its state i.e. if it is a good conductor or a bad conductor. Good metal conductors include gold, silver and copper down to the worst conductors like wood and THERMAL INSULATING MATERIALS.

Gases and liquids are also bad conductors BUT are prone to the other, convection.


The requirement for solids to lose or gain heat by this process it must be in contact with the liquid. Convection happens when a change in temperature happens in parts of the fluid thus causing the liquids density to alter. This is called ‘natural convection’. If the fluid in instead displaced and accelerated by wind or artificial factors then it is called ‘forced convection’. In forced convection the process of convection can be increased substantially.


This is how heat is emitted from a body and transmitted across a space as energy. This kind of radiation is similar to radio and light waves. It does not even need air in between for it to happen, and works just as well in a vacuum. Every solid body emits energy but the rate of emission all depends on three different things:

o Distance between surfaces

o The emissive of the surfaces (shiny and light/matt and dark)

o Temperature differences between receiving and radiating surfaces

House insulation

The application of thermal insulation does not have the effect of generating heat in your house. It is still always the rule that you will have to supply heat from an inside source. There may be a rise in temperature inside the building after the installation of insulation but that will be down to the better performance and energy saving properties of better house insulation.