Are incandescent bulbs stuffed with nitrogen? Both yes and no. First, some bulbs still require a vacuum. These bulbs are usually small and yellow-glowing, such as long aquarium bulbs, exit signs, lectern bulbs, and screw-in Christmas lights. These filaments don’t have to be run at bright white temperatures like standard incandescent light bulbs. The hot tungsten filament evaporates slowly at lower temperatures. This is because the deposited tungsten that evaporated from the filament slowly turns the glass orange/black. Argon at low pressure, few-Torr near vacuum is the fill-gas used to power most light bulbs. This invention was made by Irving Langmuir. The light bulb’s gaseous components prevent the tungsten filament from vaporizing. This would otherwise cause the filament to become blackened and reduce its lifespan. Argon is a noble gas that costs less than nitrogen and oxygen. It doesn’t affect the tungsten filament in the same way as nitrogen or oxygen. Krypton and Xenon can also be used as fill gases, but they are extremely rare and expensive and are often limited to small flashlight bulbs. Pure argon can cause electrical breakdown and long electric arcs may appear in an argon atmosphere at a low voltage. An electric arc can jump between broken ends in a pure-argon lamp. The arc-plasma can then crawl to the filament support wires and draw high current, hundreds of watts and explode the bulb. A surge/spike in the power-line could cause a similar destructive arc inside a bulb. You may have seen a lightbulb suddenly glow fiercely blue-white and then shatter or burn with a bang. This was caused by an electric arc within the argon fill gas. Add nitrogen to the solution! A tiny amount of nitrogen (less than half a %) will increase the gas-discharge voltage. A small amount of nitrogen is added in 120V bulbs to increase the voltage. This can greatly reduce the arcing effect caused by pure argon. Yes, there is some nitrogen in the bulbs. Your bulbs mostly contain vacuum…plus Argon gas at only a small percent of atmospheric pressure. For certain low-brightness yellow bulbs, the filling is vacuum. This is the same as the Edison bulbs of the 1800s. PS Stackexchange physics discovered this: Physics Education. Test pressure inside bulbs. Modern incandescent bulbs contain a vacuum but not a hard vacuum. They have a few Torr and less than 1/100th of an ATM. However, they are not as strong as vacuum tubes.