Incandescent light bulb granted a Hungarian patent (No. 34541) for a tungsten filament lamp that lasted longer and gave brighter light than the carbon filament. Tungsten filament lamps were first marketed by the Hungarian company Tungsram in 1904. This type is often called Tungsram-bulbs in many European countries. Filling a bulb with an inert gas such as argon or nitrogen slows down the evaporation of the tungsten filament compared to operating it in a vacuum. This allows for greater temperatures and therefore greater efficacy with less reduction in filament life. In 1906, William D. Coolidge developed a method of making "ductile tungsten" from
Phase-out of incandescent light bulbs the technology becomes available. Utah has also undertaken a number of LED based lighting projects to regain efficiency. In December 2007, the federal government enacted the Energy Independence and Security Act of 2007, which contains legislation to make incandescent light bulbs more efficient by setting maximum wattage requirements for all general service incandescent light bulbs producing 310–2600 lumens of light. Light bulbs outside of this range are exempt from the restrictions. Also exempt are several classes of specialty lights, including appliance lamps, rough service bulbs, 3-way, colored lamps, stage lighting, plant lights, candelabra lights under 60 watts, outdoor post lights