On every light, within the Transform category, you will find a property called Mobility.
Within it are 3 settings, Static, Stationary, and Movable, and each dramatically changes the way the light works and their impact on performance.
A completely static light that has no overhead during a running game.
Light type that can change its color and brightness at runtime but cannot move, rotate or change influence size.
A fully dynamic light capable of changing all of its properties during runtime.