The electromagnetic radiation still turns to waste heat.
So a 15W LED light would only need 3W of cooling? It feels even more ridiculous when we put the numbers like this... There is no excuse for LED lights to not have adequate cooling or for them to fail because of overheating...
> This means that about 80 percent of the electrical energy is converted to light, while 20 percent is lost and converted into other forms of energy such as heat.
That same logic might still apply for modern light solutions like LEDs. I have a more expensive LED bar which is build on top of aluminium to disperse the heat.
Did you have heard about the Dubai Lamp? It’s basically a very efficient longlife LED which they only sell in UAE.
They are damn impressive, but not "forever".
One small exception may be microntollers that use PWM to emit a signal through an antenna, or to drive a motor. I think in that case some of the energy becomes radio waves (which may never be absorbed entirely so they may not become heat) or motion in the motor.