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LED Lighting Glossary

42+ essential terms explained by Auvolar's lighting experts. From beam angles to utility rebates, understand every aspect of commercial LED lighting.

B

Beam Angle

The angle between the two directions where light intensity falls to 50% of the maximum. Narrow beam angles (15°-30°) are used for spotlighting, while wide angles (90°-120°) are used for general area lighting.

Bollard Light

A short, vertical post light (typically 3-4 feet tall) used for pathway, walkway, and landscape illumination. Common in commercial parks, campuses, and retail centers.

C

Canopy Light

A surface-mounted fixture designed for covered outdoor areas like gas station canopies, parking garage ceilings, and building overhangs. Typically rated IP65 for moisture resistance.

CCT (Correlated Color Temperature)

Measured in Kelvin (K), CCT describes the color appearance of light. 3000K is warm white (yellowish), 4000K is neutral white, and 5000K is daylight/cool white. Commercial applications typically use 4000K-5000K.

CRI (Color Rendering Index)

A scale from 0-100 measuring how accurately a light source renders colors compared to natural light. CRI 80+ is standard for commercial lighting; CRI 90+ is required for retail, healthcare, and art galleries.

D

Dark Sky Compliant

Lighting designed to minimize light pollution by directing light downward. Required in many municipalities. Full-cutoff fixtures with zero uplight are dark sky compliant.

Dimmable / 0-10V Dimming

Most commercial LED fixtures use 0-10V dimming protocol, where a low-voltage signal adjusts brightness from 10-100%. Other methods include DALI, TRIAC, and PWM dimming.

DLC (DesignLights Consortium)

An independent organization that tests and certifies commercial LED products for energy efficiency. DLC-listed products qualify for utility rebates of $20-$150+ per fixture. DLC Premium is the highest efficiency tier.

Driver (LED Driver)

The power supply that converts AC line voltage (120V/277V/480V) to the DC voltage/current needed by LEDs. Mean Well and Inventronics are common driver brands. Driver failure is the most common LED fixture issue.

E

Efficacy (Lumens per Watt)

The measure of how efficiently a light source converts electricity into visible light. Modern LEDs achieve 130-200+ lumens per watt. DLC Premium requires ≥135 lm/W for most categories.

ETL Listed

Safety certification from Intertek (ETL) indicating a product meets UL/ANSI safety standards. Equivalent to UL listing and accepted by all US building inspectors and code authorities.

F

Flood Light

A high-intensity fixture that projects a broad, even beam of light over a large area. Used for sports fields, security, signage, and building facades. Available from 50W to 1800W.

Foot-Candle (FC)

A unit measuring the amount of light falling on a surface. One foot-candle equals one lumen per square foot. Warehouses need 30-50 FC, offices 30-50 FC, retail 50-75 FC, and sports fields 30-100+ FC.

H

HID (High-Intensity Discharge)

Older lighting technology including metal halide (MH), high-pressure sodium (HPS), and mercury vapor. LEDs use 50-70% less energy than HID with better color quality and instant-on capability.

High Bay Light

Fixtures designed for spaces with ceiling heights of 15-45 feet. UFO (round) and linear (rectangular) styles are available. Common in warehouses, manufacturing, gymnasiums, and distribution centers. Typical wattages: 100W-240W.

I

IES File

A standard data file (.ies) that describes the light distribution pattern of a fixture. Used in photometric design software (AGi32, DIALux) to create accurate lighting layouts.

IK Rating

A rating measuring impact resistance of a fixture's enclosure. IK08 means it can withstand 5 joules of impact; IK10 (the highest) withstands 20 joules. Stadium and sports lights need IK10.

IP Rating (Ingress Protection)

A two-digit rating for dust and water protection. First digit (0-6) = dust, second digit (0-8) = water. IP65 = dust-tight + water jets. IP66 = dust-tight + powerful jets. IP67 = dust-tight + temporary immersion.

L

L70 Rating

The estimated time (in hours) when an LED's light output drops to 70% of its initial lumens. Quality commercial LEDs have L70 ratings of 50,000-100,000+ hours (11-22+ years at 12 hrs/day).

LED (Light Emitting Diode)

A semiconductor device that produces light when electrical current passes through it. LEDs are 50-80% more efficient than traditional lighting, last 5-25x longer, and contain no mercury.

LED Corn Bulb

A retrofit LED bulb shaped like a corn cob, designed to replace HID bulbs in existing fixtures. Available in mogul (E39) and medium (E26) bases, 36W-150W, replacing 100W-600W HID.

LED Troffer

A recessed rectangular fixture that fits into drop ceiling grid systems (2x2 or 2x4). Replaces fluorescent troffers in offices, schools, and retail. Typical wattages: 30-50W replacing 64-128W fluorescent.

LED Tube

A tubular LED lamp replacing fluorescent T8, T5, or T12 tubes. Type A (ballast-compatible), Type B (direct wire/ballast bypass), and Type C (external driver) installation methods available.

Light Distribution Type

IESNA classification for how an outdoor fixture distributes light. Type I = narrow/linear. Type II = wider roadway. Type III = forward throw (parking lots). Type IV = forward semicircular. Type V = symmetric/square (intersections).

Linear High Bay

A rectangular high bay fixture offering wide, uniform light distribution. Best for narrow aisles, racking areas, and assembly lines. Available 165W-320W.

Lumen

The unit measuring total visible light output from a source. More lumens = brighter light. A 100W LED high bay produces ~15,000 lumens; a 200W produces ~30,000 lumens.

Lux

The metric unit of illuminance. One lux equals one lumen per square meter. 1 foot-candle ≈ 10.764 lux. Used internationally for lighting level specifications.

M

Motion Sensor

An occupancy/vacancy sensor that automatically dims or turns off lights when no motion is detected. Reduces energy usage by an additional 30-50% beyond LED savings. Common in warehouses and parking garages.

P

Photocell

A light-sensing device that automatically turns fixtures on at dusk and off at dawn. Standard for outdoor wall packs, area lights, and security lighting.

Photometric Design

A professional lighting layout using software (AGi32, DIALux, Visual) to calculate and visualize light levels, uniformity, and fixture placement for a specific space. Auvolar offers this service free for any project.

Power Factor

A measure of how efficiently a fixture uses electrical power. Power factor >0.9 is considered good. DLC requires power factor ≥0.9 for most commercial fixtures.

R

Rebate (Utility Rebate)

A financial incentive from utility companies for installing energy-efficient lighting. DLC-listed LED fixtures qualify for rebates of $20-$150+ per fixture. Rebates can cover 30-70% of fixture cost.

S

Shoebox Light

A rectangular area light fixture mounted on a pole, resembling a shoebox in shape. The standard choice for parking lots, roadways, and large commercial outdoor areas. Also called area light.

Strip Light

A narrow, linear surface-mounted fixture for utility areas. Available in 4ft and 8ft lengths, 32-80W. Used in workshops, laundry rooms, storage areas, and garages.

Surge Protection

Built-in protection against voltage spikes from lightning or power grid events. Commercial LED fixtures typically include 6kV-20kV surge protection. Higher ratings are recommended for outdoor fixtures.

T

THD (Total Harmonic Distortion)

A measure of power quality. Lower THD means cleaner power draw. DLC requires THD <20% for most fixture categories. Good commercial fixtures achieve THD <10%.

Title 24

California's building energy efficiency standards. Requires specific lighting power densities (LPD) by space type. Most LED fixtures easily meet Title 24 requirements due to high efficacy.

U

UFO High Bay

A round, compact high bay LED fixture shaped like a UFO/flying saucer. Popular for warehouses, gyms, and manufacturing due to compact size, light weight, and easy installation. 100W-240W, replacing 250W-600W HID.

UL Listed

Safety certification from Underwriters Laboratories indicating a product has been tested and meets safety standards. Required by most US building codes. UL/ETL listing is mandatory for commercial installations.

V

Vapor Tight Light

A sealed, gasketed fixture rated IP65 or higher for use in wet, dusty, or corrosive environments. Used in car washes, food processing, cold storage, parking garages, and industrial wash-down areas.

W

Wall Pack

A fixture mounted on building exterior walls for perimeter and security lighting. Available as full-cutoff (dark sky compliant) or semi-cutoff styles. Typical wattages: 20W-120W.

Watt (W)

A unit of electrical power consumption. LEDs produce more light per watt than any other commercial lighting technology. A 150W LED replaces a 400W metal halide while producing equal or better illumination.

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