Copper is a metal commonly used for electrical wiring in houses. which metal conducts electricity better than copper at 20°c?

The correct answer is silver metal.
Conductivity measures the ability of a material or a metal to transmit energy, conductivity may be electrical, thermal or acoustical conductivity. The most electrical conductive element is silver, followed by copper and Gold. Silver also has the highest thermal conductivity as compare to any element. However, copper and Gold are more often used in electrical applications since copper is less expensive and gold has a much higher corrosion resistance.