A sensor apparatus includes a sensor, a heat pipe, and a cover. The sensor includes a sensor housing. The sensor housing includes a sensor window oriented generally vertically and a top surface fixed relative to the sensor window above the sensor window and oriented generally horizontally. The heat pipe is fixed relative to the sensor, wherein the heat pipe is elongated from a first end to a second end, the first end is contacting the top surface, and the second end is spaced from the top surface. The cover covers the top surface and the heat pipe, and the cover is shaped to define a vertical gap between the top surface and the cover.