Silver is the metal that conducts heat the fastest. The thermal conductivity of silver is 420 W/ (m• K) or watts per meter degrees of Kelvin. Thermal conductivity measures the ability of heat or thermal energy to move through materials.
In terms of thermal conductivity, the three materials from highest to lowest that are good heat conductors are silver, copper and gold.
Factors that affect how fast a metal conducts heat include the number of free electrons it has and how fast these electrons move. Metals are better heat conductors than non-metals.
Because there is a close correlation between thermal conductivity and electrical conductivity, materials that are good heat conductors generally also are good electrical conductors. Silver also has the highest electrical conductivity.