LED Lighting Glossary

When it comes to LED technology in lighting, there are special terminologies used to determine specifications of lamps and fixtures. It comes in handy to know and understand what these terms mean when you are selecting your new LED light bulb or fixture to make sure you choose the correct product.

Light Source

Light source is used to describe the technology that is emitted from bulbs and fixtures.


Wattage means how much power a fixture or lamp is consuming. It is calculated by multiplying voltage to the ampere.

Input Voltage

Input voltage is how much power is required to power a fixture or lamp for it to work. Fixtures and lamps use either line voltage or low voltage. Line voltage is the standard 120-277V. Low voltage is achieved with the use of a transformer to reduce the voltage down to 12-24V.


Color rendering index or CRI is a way to measure how accurate a light source can display the true color of objects when compared to natural light. The higher the CRI means that the light source is close to natural light. Fixtures and lamps with an 80+ CRI or higher, are the best at mimicking the look of natural light.


Lumens is used to describe the amount of light and LED fixture or bulb produces. It will let you know how bright a fixture or lamp is going to be, the higher the lumens, the brighter it will be.

Lumens Per Watt

Efficiency is measure in lumens per watt (lm/w) and resembles how energy efficient a lighting fixture or light bulb is. The higher lumens per watt number is, means the fixture or lamp produces more lumens with a lower wattage.

Dimming Control

LED fixtures that are listed as dimmable are compatible with specific dimming technologies. 0-10V dimming means that a 0-10V current is required to control the light intensity level. Triac dimming uses standard LED, CFL, or incandescent dimmers. Other types of dimming include forward phase, reverse phase, and low voltage dimming.

Rated Life

The rated life span of an LED fixture or bulb is measured in the amount of time it takes until the light output or lumen maintenance reaches 70% of the initial output (L70). LED rated lifespan is measure in hours and the standard for all LED fixtures and bulbs is 50,000 hours.