LED lighting use special terms and definitions to describe certain specifications or characteristics, for light bulbs and fixtures. Below is some of the most common terms that are related to LED lighting or technology. Many of these terms will give you a better understanding on the product you may be looking for.
Light source is used to define the technology that is being produced from a bulb or fixtures. Common lighting technologies include LED, incandescent, fluorescent, metal halide, high pressure sodium, halogen and mercury vapor. LED technology is the most energy efficient and with the longest lifespan compared to all of the others.
Footcandle is used to define the illuminance on a one square foot surface from a uniform source of light. Footcandles are the unit of measurement used by lighting professionals to calculate the light levels for commercial and outdoor spaces. Certain footcandle levels are recommended for different types of areas and tasks to ensure the appropriate light levels are met.
Lumens is used to define the brightness or the amount of light an LED bulb or fixture produces. The higher the lumen output, the brighter the fixture or lamp is.
Wattage is the amount of electrical power consumption a LED bulb or fixture requires. Wattage is measure in watts and is calculated by multiplying voltage to the ampere.
Color temperature is a way of describing the light color by using kelvins, the unit of measure for temperature. Color temperatures are described as 2400K very warm white, 2700K warm white, 3000K soft white, 3500K neutral white, 4000K or 4100K cool white, 5000K daylight, and 6500K full spectrum.
Input voltage describes how much load is required for the fixture to work. Typically most LED fixtures feature a universal input voltage of 120-277V, with some having 347-480V options for different commercial lighting applications. Most LED bulbs have an input voltage of 120V.
Color rendering index or CRI is the way to measure how accurately a light source can display the true color of an object when compared to natural lighting. Higher numbers mean that this light source is close to natural light. Numbers that are higher than 80+ CRI are very well in being the most similar to natural light.
Efficacy is measured in lumens per watt (lm/W) and details how energy efficient a lighting fixture is. The higher efficacy means the fixture produces more lumens with lower wattage.
There are two types of dimming when it comes to LED fixtures, one is 0-10V dimming which requires a 0-10V current to control the light intesity level. The others are triac, reverse phase, forward phase, and low voltage dimming, which use regular LED/CFL or incandescent dimmers.
The lens type describes what covers the LED lamps on a fixture, they can be made of glass, acrylic, or polycarbonate, with some having a clear or frosted diffuser to diffuse the light.
The operating temperature is the temperature range an LED bulb or fixture operates effectively.
Rated hours or rated life measures the time the light output or lumen maintenance of an LED lamp or fixture to reach 70% of the initial output (L70). The LED lifespan is measured in hours and the standard for all LED fixtures is an L70 of 50,000 hours.