Light Bulb 101: How LED's Work
According to ENERGY STAR, the lifespan of LED lighting products is defined differently than that of other light sources, such as incandescent or CFL. This is because LEDs typically do not “burn out” or fail. Instead, they experience lumen depreciation, where the amount of light produced decreases and light color appearance can shift over time.
Instead of basing the useful life of an LED product on the time it takes for 50% of a large group of lamps to burn out (as is the case with traditional sources), LED product “lifetime” is set based on a prediction of when the light output decreases 30 percent.
LEDs and Heat
LED lighting systems do not produce heat like other bulbs. The heat produced from the power going into the product must be drawn away from the LEDs. This is usually done with a heat sink, which is a passive device that absorbs the heat produced and dissipates it into the surrounding environment. This keeps LEDs from overheating and burning out.
When an LED light is turned on, electricity is sent through the semi-conductor and the LED chip is illuminated. The light produced then goes through the lens while the heat from the reaction is dispersed through a heat sink. Modern heat sinks are so effective that many LED lamps are cool to the touch.
What Are Lumens?
A lumen is technically defined as one candela multiplied by one steradian. In layman’s terms, one lumen is equivalent to the light produced by one birthday candle from one foot away. To expand this idea, seeing 100 lumens is like standing one foot away from a cake with 100 birthday candles on it.
Lumens, unlike watts, are a direct measure of light output. Therefore, a larger lumen count means a brighter bulb.
Why Not Watts?
While lumens directly measure light output, wattage measures the energy each light uses. Historically, incandescent bulb brightness was directly determined by their wattage.
However, energy efficient lighting options like LEDs and CFLs are able to produce more lumens with far less energy. To regulate which bulbs are truly the brightest, government regulations now mandate each lighting product accurately lists its lumen count.
How Can I Find An LED That Produces Enough Light?
Each TCP LED package lists the lumen count and also its incandescent equivalent. For instance if a TCP 12 watt LED is listed as a 75 watt incandescent equivalent, it will produce the same amount of light as an old 75 watt bulb.
Once you become accustomed to the new system you can begin to pick your lights based on lumen count.
How Long Will My LED Lighting Last?
TCP adheres to an industry standard for rating lightbulb life called “rated life.” This figure is listed on every TCP LED product.
Rated life is determined through vigorous lamp testing. The time that half of the test samples fail is considered rated life. By definition, some lamps will fail before their rated life while others will exceed it.
Always bear in mind that using an LED in an improper application or old wiring can have a negative impact on the lamp’s life. Application information can be found on the bulb packaging.
How Does Color Temperature Affect LED Lighting?
The color temperature of a light determines the color of its light. Warm color temperatures (2700K-3000K) appear to have a yellow hue while lights with high color temperatures (5000K) have a blue tint.
Each color temperature has its own unique qualities and uses: