Avitech AviTemp Ceramic Heat Emitter (150 watt) Ceramic heat elements have no delicate filaments and will last up to 4 times longer than glass heat bulbs Glass heat bulbs may waste up to 25% of their energy as light. AviTemp heat elements are completely dark so that normal sleep cycles are preserved. Higher wattage AviTemp elements can be used outdoors if protected against rain and snow. These are screw-in infrared elements that are a must for all bird lovers.