Lighting fixtures and retrofit kits hard wire into an electrical system to supply indoor illumination. Fixtures for general area lighting include bay lights for high ceilings or open trusses, panels and troffers for grid ceilings, and surface-mount fixtures for drywall surfaces. Fixtures for smaller areas and accent lighting include can, track, decorative, and under-cabinet lights. Other fixtures provide light for specific settings (hazardous locations, dusty or damp locations, high-abuse areas, or healthcare) or specific applications (disinfection or plant growth). Retrofit kits convert existing fixtures to LED or more energy-efficient, fluorescent bulbs without having to switch out the entire fixture.