The watt input between a bulb and a heater may be similar, but the
efficiency of heat transfer is related to surface area that can
radiate. A bulb has a tiny area compared to the surface area of an
electric heater and in a finite time will distribute its heat energy
less efficiently than a larger surface area heater.
In an infinite time span in a closed environment, the bulb and heater
will achieve almost a similar heat distribution. Since we don't have
infinite or even long time spans, a large surface area heater wins
everytime.

On 2005-11-26, nollaigoc wrote:

The watt input between a bulb and a heater may be similar, but the
efficiency of heat transfer is related to surface area that can
radiate.

how is it related to that?
what are you proposing happens to the "extra" energy?

A bulb has a tiny area compared to the surface area of an
electric heater and in a finite time will distribute its heat energy
less efficiently than a larger surface area heater.

lightbulbs (and other radiant heat sources) tend to heat opaque objects
faster than they heat the air.

a heater with a large hot suurface puts most of its energy into the air.

In an infinite time span in a closed environment, the bulb and heater
will achieve almost a similar heat distribution. Since we don't have
infinite or even long time spans, a large surface area heater wins
everytime.

no, it depends what you are trying to heat.

Bye.
Jasen