An LED lamp includes a housing having a base, a frame at a top end of the housing and a plurality of stanchions interconnecting the base and the frame. A heat sink is mounted on the frame. An LED module is received in the housing and attached on a bottom surface of the heat sink. A printed circuit board is arranged on the base of the housing, and a reflector is located on the printed circuit board. A transparent envelope is received in the housing and covers windows defined between the stanchions. A light generated by the LED module is reflected by the reflector to transmit outwardly through the envelope to illuminate a surrounding environment.