Heating Element Efficiency

[coffee]

Does anyone know what typical efficiencies are for a resistive heating element submerged in water? I am interested in the efficiency of converting electrical energy to heat energy in an application like a home hot water heater. I am not interested in how efficiently the unit stores heat.

 

[tlutz]

Conversion of electrical energy to heat energy is 100% efficient within a resistive heating element. There is no other form of energy involved (ie the electricity is not converted to light, motion, chemical energy, etc). With other devices such as motors, inefficiencies turn up as heat. With heaters, all of the energy converts to heat, so if the objective is to produce heat, they are 100% efficient.

There will be a small amount loss due to heat conduction at the mounting point of the heater, and through the "cold pin" of the heating element which connects the electrical terminal outside the heater to the internal resistance wire, but these are small compared to the overall storage losses and generally may be neglected.