Incandescent light bulb Small variations in resistivity along the filament cause "hot spots" to form at points of higher resistivity; a variation of diameter of only 1% will cause a 25% reduction in service life. These hot spots evaporate faster than the rest of the filament, which increases the resistance at that point—this creates a positive feedback that ends in the familiar tiny gap in an otherwise healthy-looking filament. Irving Langmuir found that an inert gas, instead of vacuum, would retard evaporation. General service incandescent light bulbs over about 25 watts in rating are now filled with a mixture of mostly argon and
Phase-out of incandescent light bulbs 2010 in favor of more energy-efficient fluorescent globes to help cut greenhouse gas emissions and household costs during her closing remarks at the Philippine Energy Summit. Once put in effect, the country will be the first in Asia to do so. The Government will stop all production, import and sales of incandescent light bulbs by or before January 2014, as part of efforts to save power and to help cut greenhouse gas emissions. Phase out of 60W and over incandescent light bulbs has been implemented from 1 January 2012. As a measure to increase awareness a national awareness campaign has