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 lives than incandescent bulbs. When bulbs are used infrequently, such as in little-used closets and attics, it may take a long time to compensate for the higher initial cost of the bulb. The overall energy savings from changing to more efficient lighting depends on the climate. In warm climates, efficient lighting has the additional energy-saving effect of reducing the amount of cooling required. In cold climates increased heating energy demand may offset some of the lighting energy saved with efficient lighting. A report published in January 2008 found that in Los Angeles, where incandescent lighting results in increased air conditioning,