These slender bulbs are used in lamps and task lights. Brightness is measured in lumens; the higher the lumens, the brighter the bulb. Bulbs with a warm light appearance have yellow tones. Bulbs with a neutral light appearance are commonly used in workspaces. A bulb’s estimated yearly energy cost is based on 3 hours of usage per day at $0.11 per kWh. These halogen bulbs are slightly more energy efficient than incandescent bulbs, but they generate more heat.