Wattage is heat (at least the power dissipated by a semiconductor is heat)... The temperature depends on how concentrated the heat is. You can melt solder with a 25W soldering iron! A heatsink spreads-out the heat and lowers the temperature.
A 100W incandescant light bulb puts-out about 10W of light and 90W of heat.
100 Watts is not enough to heat-up a room, but it's enough to make a light bulb too hot to touch! Actually, when the light is absorbed by an object, the light is converted to heat also. (I don't think you can melt solder with a light bulb because of the larger surface area... I'll have to try that! 
But, the filiment inside the light bulb is certainly hot enough to melt solder.)