LED light becomes extremely hot
Russell commented in a recent answer that efficiency(*) up to 20 % is possible. That's 4 or 5 times the efficiency of an incandescent bulb. So we're doing fine here. But of course, a 20 W LED lamp will still produce 16 W in heat (that bulb would have 19 W in heat). And if it comes with a heat sink, better leave it as it is; it's there for a reason.



(*) I'm using the word "efficiency" here because that's the word used for it in everyday language. Szymon correctly points out that "efficacy" would be better, expressed in lumen per watt. Actual efficiency as Szymon uses the word is always 100 %, because that's the ratio energy out/energy in, due to the laws of thermodynamics.