An insulator is a material or method that restricts the transfer of either heat or electricity.Insulators are used to protect us from the dangerous effects of electricity flowing through conductors. Insulators are materials that have just the opposite effect on the flow of electrons.They do not let electrons flow very easily from one atom to another.nsulators are used to protect us from the dangerous effects of electricity flowing through conductors. Insulators are materials that have just the opposite effect on the flow of electrons.