https://www.ledsmagazine.com/leds-ssl-design/thermal/article/16696536/fact-or-fiction-leds-dont-produce-heat
Interesting article about led lamps. Apparently LED's only produce 15% light??
It is getting a bit more than that now (20..25% is becoming a common place, depends a bit on the color conversion - one blue photon forms no more than one e.g. red photon in the phosphor, but the red one carries less energy, the difference then became heat), but ball-park it is indeed correct.
But honestly it is a lot, it mainly shows how little energy is within a seemingly lot of light...
