Energy Saving Lightbulbs in Energy Posted June 11, 2014 · Report post Hopefully, they will all be replaced by LEDs once the technology needed to dissapate the heat appears. They are a lot more efficient but the heat sinks really hurt their environmental friendliness and price effectiveness. I've never heard anyone complain about LEDs being too warm or waste too much energy. LEDs are perfect for locations where more traditional light sources - or even CFLs - can cause a problem. Mind you, that is not to say that LEDs don't produce heat, or that even more energy could be saved. As the author here notes: "[...] heat is produced within the LED device itself, due to the inefficiency of the semiconductor processes that generate light. The wall-plug efficiency (optical power out divided by electrical power in) of LED packages is typically in the region of 5-40%, meaning that somewhere between 60 and 95% of the input power is lost as heat."