Only a small amount of the energy used in an incandescent light bulb (regular bulbs commonly used in households) is actually converted into light. What happens to the rest of the energy? How more efficient light bulbs (LEDs for example) are able to waste less energy?

Incandescent lamps are characterized by converting energy into light and heat, which makes you consume more. Only 5% of the energy generated is converted into light. The remaining 95% is transformed into heat, which explains the great waste they generate. On the other hand, the most modern lamps, such as LED lamps, are entirely electronic, composed of one or more light-emitting diodes, that is, electrical semiconductors manufactured with aluminum and gallium arsenide, among others, that when receiving energy convert it into light, generating much less heat than incandescent lamps, which means less loss.