Sunlite halogen BT15 bulbs can last up to 1.8 years with normal household use of 3 hours a day and display a brighter, whiter light than incandescent bulbs. This 150 watt, medium based, BT15 bulb offers a light output of 2100 lumens, a white glass finish and has an average rated life of 2,000 hours. Great for portable lamps, ceiling fixtures, track lighting, showcase displays and most common residential and commercial lighting needs. Halogen bulbs produce more lumens per watt (LPW) and have a longer lamp life than standard incandescent lamps. You can lower operation costs by more than 30% by using fewer halogen lamps to produce a greater amount of light.