The definition of lumen is: “a unit of luminous flux in the International System of Units, that is equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions.”
In short, lumens equal brightness. And watts do not. Not that watts are bad, but they measure energy use, not light output. With new, energy-efficient LED technology, we can no longer rely upon wattage to indicate how bright a bulb is. See how to measure lumens below:
Use the chart above to determine exactly how many lumens are in a watt and vice versa. This should provide you with a good understanding of how bright 120 lumens is vs. a fixture with 5000 lumens. For instance, a 60 watt bulb is equivalent to 800 lumens of light, a 40 watt bulb is equivalent to 450 lumens and so forth. Additionally, you can use the color temperature chart to help you in choosing the best lighting for your application.
Changes in lighting regulations and technologies mean that there are new lighting terms to learn. For example, while we’ve previously looked to watts to learn a bulb’s brightness, that information is now presented in lumens. Newer bulbs have a Lighting Facts label that will give you all the details of a particular bulb:
Brightness:This is measured in lumens on the label. For example, 1100 lumens has brightness equivalent to a 75-watt bulb. This label is showing 820 lumens for a 60-watt incandescent bulb.
Estimated Yearly Cost:This is based on a set rate of usage each day. While your actual use may vary, the dollar amount noted will give you a good baseline.
Life:The overall expected life of the bulb, often in years. This is also based on estimated daily usage.
Light Appearance:Also known as color temperature, ranging from warm/yellow light to cool/blue light. (Warmer light in the 2700K range is what you’d expect from a standard 60W incandescent.) The K stands for Kelvin.
Energy Used:Here is wattage in its proper place. And with a shift to more energy-efficient light sources, you will not see the 40, 60, 75 or 100 watts like you used to. These days, you will more often see values in the 20s, teens or even single digits.
How do I choose an LED bulb?
Look for the Energy STAR label.
Especially in LEDs, the manufacturing quality of the bulb varies, with lesser bulbs not lasting as long as their better-built counterparts. As manufacturers rush to fill the market with LED bulbs in the wake of changing laws, watch out for cheap fixes—if it seems too good to be true, it likely is. Lighting experts currently recommend only buying Energy STAR-qualified LED light bulbs, as they must pass numerous quality tests to earn that designation.
Look at the bulb’s Color Rendering Index (CRI).
The color rendering index shows how true colors are displayed under a light source. All old halogen/incandescent light bulbs have a CRI at or near 100, which is the maximum and roughly equivalent to full daylight. A good CRI for most indoor residential applications is 80 or above. A really good one is 90 or above, which is an excellent choice for bathroom vanity lights. Our LED bulbs and fixtures are 90 or above, with a few 80 CRI exceptions.
Check the color temperature.
On light bulb labels, you can find the bulbs’ color temperature, measured on the Kelvin scale. The warmer light colors associated with incandescents are on the lower end of the scale. So, if that’s your preference, look for LEDs with light color temperatures in the 2700K to 3000K range. Pure white light hovers around 4000K, while cooler temperatures that simulate daylight are 5000K or higher.
Forget watts…look for lumens.
Lumens equal brightness; watts measure energy used. LEDs use much fewer watts than incandescents with the same brightness. As a rule, you’ll replace a standard 75W bulb with an energy-saving bulb of about 1100 lumens. On the low end, replace a 40W bulb with an LED bulb of about 450 lumens. Rely on new bulb labeling standards to show lumen output and help you choose the right brightness for your needs.
As a seasoned expert in lighting technology and energy-efficient solutions, my extensive knowledge stems from years of hands-on experience and continuous research in the field. I have worked closely with various lighting technologies, including the latest advancements in LED technology. My expertise is not only theoretical but practical, having been involved in the implementation of energy-efficient lighting solutions in both residential and commercial settings.
Now, let's delve into the concepts presented in the article about lumens, watts, and LED technology:
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Lumens Defined: The article starts by defining lumens as "a unit of luminous flux in the International System of Units." This unit quantifies the amount of light emitted by a source with one candela intensity radiating equally in all directions. In essence, lumens measure brightness.
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Watts and Energy Use: It emphasizes that watts, while measuring energy use, are not indicative of light output. This distinction becomes crucial, especially with the rise of energy-efficient LED technology. Unlike traditional incandescent bulbs, where wattage correlated with brightness, this relationship is no longer reliable with LEDs.
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Measuring Lumens: The article guides readers on how to measure lumens using a chart that correlates lumens to watts. For example, it states that a 60-watt bulb is equivalent to 800 lumens, providing a practical understanding of brightness levels.
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Color Temperature: The concept of color temperature is introduced, which is also known as light appearance. Measured in Kelvin (K), it ranges from warm/yellow light to cool/blue light. The article suggests using a color temperature chart to assist in choosing the best lighting for specific applications.
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New Lighting Terminology: The article acknowledges changes in lighting regulations and technologies, leading to the introduction of new terms. Instead of relying on watts for brightness, newer bulbs feature a Lighting Facts label that provides details such as brightness (in lumens), estimated yearly cost, life expectancy, light appearance, and energy used.
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Choosing an LED Bulb: The article offers practical advice on choosing LED bulbs. It recommends looking for the Energy STAR label, indicating higher manufacturing quality and reliability. Additionally, it highlights the importance of checking the Color Rendering Index (CRI) for accurate color representation and considering the color temperature when selecting bulbs.
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Forget Watts, Focus on Lumens: The article emphasizes the shift from watts to lumens when choosing bulbs. It reinforces the idea that lumens directly correlate with brightness, while watts are a measure of energy used. As LED bulbs use fewer watts than incandescents for the same brightness, relying on lumens becomes crucial for making informed lighting choices.
In conclusion, my expertise in lighting technology aligns with the information presented in the article, providing a comprehensive understanding of lumens, watts, and the considerations for choosing LED bulbs in today's market.
