Incandescent light bulbs are considered to be lower efficiency than LED bulbs for several reasons:
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Energy Conversion: Incandescent bulbs work by heating a tungsten filament until it glows, producing light. However, a significant amount of the energy consumed (about 90%) is lost as heat rather than converted into visible light. In contrast, LED (Light Emitting Diode) bulbs convert a much higher percentage of energy into light, making them more efficient.
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Luminous Efficacy: The luminous efficacy of a light source is measured in lumens per watt (lm/W). Typical incandescent bulbs have a luminous efficacy of about 10-17 lm/W, while LED bulbs can achieve 80-100 lm/W or more, meaning they produce significantly more light per unit of energy consumed.
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Lifespan: Incandescent bulbs generally have a shorter lifespan than LEDs, often lasting about 1,000 hours compared to 15,000 to 50,000 hours for LEDs. This shorter lifespan leads to more frequent replacements, which can contribute to higher overall energy and resource use when considering the full lifecycle.
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Heat Generation: Because incandescent bulbs emit a large amount of heat, they not only waste energy but can also contribute to increased cooling costs in warm environments. LED bulbs produce very little heat, reducing energy consumption for air conditioning in those spaces.
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Environmental Impact: The higher efficiency and longer lifespan of LED bulbs result in less energy consumption over time, leading to lower greenhouse gas emissions during electricity generation and a reduced environmental impact compared to traditional incandescent bulbs.
In summary, the combination of energy loss as heat, lower luminous efficacy, shorter lifespan, and greater environmental impact makes incandescent light bulbs significantly less efficient than LED bulbs.