Incandescent lamps have very low energy efficiency, converting only 10-20% of energy input into light with the rest lost as heat. However, they have low initial cost, are simple to replace, provide excellent color rendition, and allow for instant start and dimming. Tungsten halogen lamps have slightly higher energy efficiency than incandescent at around 22 lumens per watt but must be handled carefully to avoid oils damaging the bulb and shortening its life, which averages only around 2000 hours. They provide high lumen maintenance, excellent color rendition, and are available in different wattages for uses like flood lighting.

1. Incandescent Lamps

3. Comparison of Sizes

4. Mains Voltage Tungsten Halogen

5. Cont. • Luminous efficacy low at approx. 22 lumens per watt • The surface of a tungsten bulb must NOT be handled with the bare fingers as the salts and oils from the hand will cause a cooler area of the bulb leading to early lamp failure. • Double ended lamps must be kept within 4 degrees of the horizontal to maintain regenerative cycle. • Average life is only about 2000 hours. • High lumen maintenance due to no bulb blackening • Low initial cost • Narrow lamp permits excellent beam control. • Color rendition is excellent. • Wide range of lamp wattages available. • Used for flood lighting, projector lamps etc. • Sizes: 500W, 750W, 1000W, 1500W Disadvantages Advantages