Is Air An Insulator? 5 Facts You Should Know!

Air is the unapparent gaseous substance enclosing the earth, a mixture generally of oxygen and nitrogen. Let us see whether air is an insulator or not.

Air is an insulator that has evaporating quality. They are bad conductors of heat because of additional separation between the molecules. Heat shift needs connection between molecules and therefore evaporating substances are commonly good insulators.

Air disperse molecular structure resist heat move to some proportion. Seeing the vital importance of air as an insulator, let us focus on why air is a good electric insulator, is air a good heat insulator, uses of air as an insulator, when does air conduct electricity and many more questions in this article.

Why is air a good electric insulator?

Air is generally a thermal insulator, but it can convey heat via convection. Let us see why is air a good electric insulator.

Air is a good electric insulator because air molecules are too far apart to govern energy competently. This intimates that electricity can be conveyed through a conductor and it will not fly across the air. In the case of electrical operations, the air has small conductance.

Though air is a good electric Insulator and also have some restriction, the restriction or limit of air is 30000 volts/cm. It is nothing but a dielectric strength of an insulator.

Is air a good heat insulator?

Heat insulation is the depletion of heat fetch between two gadgets in thermal contact. Let us see whether the air is good heat insulator or not. 

Air is a good heat insulator because valence electrons are withheld tightly and the heat to shift via that material is dense also air is a gaseous substance so it is turn out that molecular customizes heat to shift to some degree.

Though air pockets inside the insulating material are segregated from one another, heat passing from one air pocket to another will not take place easily because it disseminates the convection of heat.

Uses of air as an insulator

Insulators have powerful bonds that clasp their particles rigorous in space. Particles in an insulator do not flow around easily. Let us see the uses of air as an insulator.

Uses of air as an insulator are listed below,

  • Double-pane window
  • Insulated coffee mugs
  • Polystyrene cups
  • Insulated house
  • Optics

 Double-pane window

The double-pane window uses air as an insulator because hot or cold air has to flow via two distinct panes of glass and it turns into hard, unfeasible for intolerable temperatures to enter your home. This obviously can deliver your energy bills substantially, during the very cold and very hot months.

Insulated coffee mugs

Air acts as an insulator in coffee mugs preventing the heat to get transformed from coffee to our hands. If we are gulping out of a paper cup, our hands will sense the hotness of the coffee. But when we gulp in an insulated cup, we may hardly sense any hotness while clasping.

Polystyrene cups

Polystyrene is made up of more than 95% of air which is a type of insulation. When we use these polystyrene cups there is only a slight variation in the outside temperature of the cup from the coffee’s hotness.

Insulated house

In the insulated house the air is used as an insulator so the outer walls, doors, and windows act as a barrier when accurately closed. If it is a cold day and the house is being heated, the walls, doors, and windows will retain the cold temperature out and the hotness inwardly.


In optics, silica aerogel has been used as an air insulator because both dispersion and immersion can diminish the amount of light disseminated via the aerogel slab. Aerogel gives very efficient insulation due to which they are highly porous and the pores are in the nanometer range.

When does air conduct electricity?

Air also behaves as a conducting medium during lightning. Let us see the situations when air can conduct electricity.

  • When the air atoms become oxidized and create a conducting passageway.  The current moves in the form of an arc.
  • In pliers, insulator part having 1000V, then these pliers in an electric field more than 1000V, the material constitution will lose its insulating capabilities and it will conduct electricity.
  • When we consider two huge charged surfaces, the air in between will break and give rise to a spark. A spark happens because the air molecules are conducting electricity.
  • When rainstorms happen, the air between mists and the land operates like a capacitor. When the electric field is greater enough, the air moderately oxidizes, at that point, there are valance shell electrons to switch current and the air becomes inherently conductive.

When does air conduct heat?

Heat is the shifting of kinetic energy from one medium or gadget to another. Let us see when air conducts heat.

The air does conduct heat in the following conditions,

  • Air in a closed container conducts heat because air is transparent and all three heat transfer mechanisms are possible that is conduction, convection, and radiation.
  • Consider the two parallel surfaces containing air between them at a small distance passing between two parallel plate surfaces then the air conduct a little bit of heat.


Let us wrap up this post by stating that air by itself isn’t that great insulator as it acts as a conductor in certain situations when it is united with something to trap the air in tiny spaces to prevent the convection currents, which is explained in the post.

Megha BR

Hi, I am Megha B R, I have completed my Post-Graduation in Solid State Physics and pursuing B. Ed. I am a Physics enthusiast. As an Academic writer, my goal is to reach the readers in a simplified manner through my articles. Let's connect through LinkedIn-

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