> i'm confused. how can they be efficient if they get hot? The reason is due to the balance between heat generated and heat dissipated into the environment. T

> i'm confused. how can they be efficient if they get hot? The reason is due to the balance between heat generated and heat dissipated into the environment. The bulb could convert 99% of the input electrical energy into light, and only 1% into heat. So for a 100W bulb, that would be only 1 watt of heat. But if the heat dissipation system (i.e., the cooling system) can only dissipate 1/2 watt of heat into the environment over the same time span that the bulb is creating 1 watt of heat, the excess 1/2 watt of undissipated heat will build up over time, making the housing hot to the touch.