Aluminum wire is a type of electrical conductor used for wiring of residential construction or houses. Aluminum provides a better conductivity to weight ratio than copper, and therefore is also used in wiring power grids and for power wiring of some airplanes. Utility companies have used aluminum wire for electrical transmission in power grids since around the late 1800's to the early 1900's. It has cost and weight advantages over copper wires. Aluminum wire in transmission and distribution applications is still the preferred material today.