Do all light bulbs run at about the same level of efficiency?

The efficiency of light bulbs varies significantly based on the type of technology they use. Traditional incandescent bulbs, for example, are less efficient as they convert only about 10% of the electrical energy into visible light, with most of the energy wasted as heat. In contrast, compact fluorescent lamps (CFLs) and light-emitting diodes (LEDs) are designed to be far more efficient, converting a higher percentage of energy into light.

LEDs can achieve efficiencies of up to 80% or more, making them the most energy-efficient option currently available. This variation in efficiency is influenced by how different types of bulbs generate light — incandescent bulbs rely on heating a filament, while CFLs and LEDs use different mechanisms that allow for greater energy transfer into light.

Consequently, saying that all light bulbs run at about the same level of efficiency is incorrect. The differences in the underlying technology lead to significant variations in how efficiently they operate.