Various implementations of an LED kit include a housing and at least one LED unit. The LED unit is coupled to an outer surface of at least one wall of the housing. Inner surfaces of the housing walls define a channel that includes a first opening at one end of the housing and a second opening at the other end of the housing. A central axis of the channel is orthogonal to a light output direction of the LED unit. A heat sink structure extends from the inner surface of at least one of the walls, and at least one electrically powered cooling device (e.g., a fan) is disposed adjacent the first opening. The cooling device causes air to flow through the channel from the first opening to the second opening, or vice versa, along the central axis and across the heat sink structure orthogonally to the light output direction.