LED light panels and troffers use significantly less energy than fluorescent troffers and have built-in LED arrays so there are no light bulbs to install or replace. LED arrays typically last for years before needing a replacement driver, so these fixtures generally require minimal maintenance. Sometimes called flat panels, these slim fixtures provide large amounts of light for offices, schools, hospitals, retail spaces, and other commercial settings. Panels and troffers are most commonly mounted in drop ceiling grids with the majority of the fixture recessed in the ceiling for a clean look that doesn't draw attention to the fixture. The height of the panel must be less than the height above the ceiling for a proper fit within a recess. LED light panels may also mount to a drywall ceiling when paired with a compatible surface-mount accessory.