How to compare LED light output to incandescent bulbs

Updated April 17, 2017

Light-emitting diode (LED) lights have been used for years in small electronics to light up displays. Advances in the design of LEDs now enable them produce enough light to compete with standard incandescent light bulbs. Since LED lights do not burn gas or depend upon filaments, they are rugged and produce very little heat, according to An added bonus of switching to LED bulbs is their lower wattage needs. A 40-watt incandescent bulb can be replaced by a 5-watt LED bulb. That will save money on the cost of lighting a building.

Locate general sources of lighting information on the Web or at the library and look for technical information related to different kinds of light bulbs. A good source of information on lighting, including LEDs, is at Also search online for books on lighting. Many books have free previews and you will be able to read all, or portions, of the content. When using the library, look for periodicals about scientific and consumer topics and scan their tables of content to see if there are articles about lighting.

Locate manufacturer sources of lighting information on the Web, or the library. Westinghouse and General Electric for example, both have light bulb products, so by reviewing their web sites or their listings in the Thomas Registry at the library you can find technical information related to their products.

Locate an LED bulb product package and an incandescent bulb product package to make a direct comparison between two specific bulbs.

Scan through the information in the sources or packages looking for references to "lumens" and "watts." You will want to know how many lumens each type of light bulb produces and how many watts of electricity it takes to produce that number of lumens.

Look at the number of lumens put out by an LED bulb and determine how that number compares with the number of lumens put out by an incandescent bulb.

Look at the number of watts required by the LED bulb to create the number of lumens it creates and determine how that number compares with the number of watts used by the incandescent bulb.


When the number of LED bulb lumens is greater than the number of incandescent bulb lumens, and the corresponding watts required to generate those lumens is lower for the LED, then the LED bulb is more efficient; if the opposite is true, the incandescent bulb is more efficient.

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