I have two questions actually: 1. According to Stefen's Law formula power created by an conventional tungsten bulb can be calculated and temperature of the filament is about 3500 K. I know it has low pressure gas inside a bulb but doesn't that mean sooner you switched on the bulb the pressure inside will reach roughly about 11 times higher! (PV=nRT... I can assume dilute gas is used and ideal gas assumption is correct) 2. Filament will carry the temperature of the gas to 3500K eventually when the system reaches equilibrium. From then that hot gas will heat the room by conduction(through bulb's thin wall) and then through convection. Then glass should melt and even if it doesn't , one bulb should produce enough heat to warm the whole room! But that doesn't happen why? where does that 3500K temperature goes to? I'm not looking at the radiation side of the problem you see. What I'm interested in here is a filament which is at 3500K and that piece of metal heats the gas inside to 3500K?? or does it?