Understanding lighting terminology is essential whether you're upgrading your home's lighting, installing a new electrical system, or working on a commercial project. The right lighting choices can enhance functionality, ambiance, and energy efficiency. Below are some key terms and concepts to help you navigate the world of lighting.

Lighting Terminology You Should Know

Lumens and Watts

Lumens measure the total amount of visible light emitted by a source. The higher the lumens, the brighter the light. In contrast, watts measure the amount of power consumed by a bulb. Traditional incandescent bulbs are rated by wattage, but with energy-efficient LED lighting, lumens are now the standard measurement for brightness. For example, a 60-watt incandescent bulb produces about 800 lumens, while an LED bulb can achieve the same brightness using only 8–10 watts.

Foot-Candle (FC)

A foot-candle is a standard unit of measure for the light shining on a surface. It equals one lumen per square foot and measures light intensity in a given area. This unit of measure is the basis for OSHA and IES standards regarding minimum light levels. 

Color Temperature

Measured in Kelvin (K), the color temperature scale rates the appearance of light emitted by a bulb. Lower Kelvin values (2700K–3000K) produce warm, yellowish light, ideal for cozy indoor spaces. Mid-range values (3500K–4500K) offer a neutral white light, often used in offices and task lighting. Higher values (5000K–6500K) emit a cool, bluish light similar to daylight, suitable for outdoor applications and areas requiring high visibility.

CRI (Color Rendering Index)

CRI measures a light source's ability to accurately reveal the colors of objects compared to natural sunlight. Rated on a scale from 0 to 100, a higher CRI indicates better color accuracy. For most residential and commercial applications, a CRI of 80 or higher is recommended, while settings requiring precise color discrimination, such as photography studios or retail displays, benefit from CRI ratings of 90 or above.

A-Lamp

The most common LED or incandescent screw-in "light bulb" that is used throughout most homes in North America. An A-lamp may have a clear glass bulb, a white coating, or an etched frost inside the glass bulb.

Average Rated Life

The average rated life is the hours required for half of a large group of lamps or bulbs to fail or burn out. The actual life of any lamp or small group of lamps will typically be different from the average rated life. 

Beam Angle

Beam angle refers to the spread of light emitted from a fixture. A narrow beam angle (10°–30°) focuses light on a specific area, ideal for accent lighting. A wider beam angle (60°–120°) disperses light more broadly, making it suitable for general illumination in large spaces. Understanding beam angles helps in selecting the right fixtures for your lighting needs.

Dark Sky Compliant

This signifies a light fixture complies with the International Dark Sky Association's (IDA) regulations for reducing ambient light pollution. The light source must be completely shielded, within maximum wattage constraints. The advantages of reducing light pollution include increased stars visible at night, reducing the adverse environmental effects of electric lighting, maximizing safety, and decreasing energy usage.

Diffused Light

Diffused light is produced by an extended surface, directly or through reflection. It provides a uniform and soft distribution that minimizes shadows.

Dimmable Lighting

Dimmable lighting allows users to adjust brightness levels to create the desired ambiance and save energy. However, not all bulbs and fixtures are compatible with dimmer switches. LED bulbs, for instance, require specific dimmable models and compatible dimmers to function properly. Before installing dimmable lighting, ensure that all components are compatible to avoid flickering or reduced lifespan.

Direct Lighting

Direct lighting is where more than 90% of the light travels directly from the source to the area intended for illumination. 

Edison Bulb

Also called an Antique Bulb or Vintage Bulb. This type of bulb replicates the popular coiled filament bulbs made by Edison Electric Light Company at the turn of the 20th century. Edison bulbs are often used in decorative fixtures and produce a warm, vintage look.

Efficacy

Describes how effectively a lighting fixture can convert electric power into lighting, measured in lumens per watt. This is similar to the gas mileage of a sports car, where the lighting output can be compared to miles traveled, and the electric power input is similar to fuel consumption.

Efficiency

The conversion ratio between lighting power output and electric power input is measured in both quantities in watts. This is not to be confused with efficacy, which describes the ratio between lumen output and watts consumed.

Energy Star® 

Energy Star® is a government-backed program to help consumers identify energy-efficient products and appliances. The program promotes energy conservation by labeling products that meet specific energy efficiency standards. Products with the Energy Star label are certified to use at least 20% less energy than federal standards require.

Fluorescent Lighting

Fluorescent light is an artificial light that uses a gas-discharge lamp to produce light. It produces light by passing an electric current through a low-pressure gas inside a sealed tube containing a phosphor coating. The phosphor coating absorbs the energy from the current and then re-emits it as visible light.

High-Intensity Discharge Lighting (HID)

HID is the acronym for high-intensity discharge, an enclosed gas lighting type that operates at high temperatures and provides a powerful light output. HID lighting includes several lighting types:

• High-pressure sodium

• Low-pressure sodium

• Mercury vapor

• Metal halide

• Xenon

Illuminating Engineering Society of North America (IESNA)

The Illuminating Engineering Society of North America is the worldwide technical authority for the lighting industry.

Indirect Light

Indirect lighting doesn't directly illuminate a space but bounces off of the room's walls, ceilings, and other surfaces to create a more diffuse, ambient light. It is often used to create a cozy and welcoming atmosphere in a room.

Landscape Lighting

Lighting that is designed explicitly for illuminating gardens, yard scapes, and outdoor pathways. Most landscape lighting operates on low-voltage systems. 

Light

Radiant energy that is capable of producing a visual sensation.

Lighting Controls

These devices give you flexibility, decorative effects, and multiple uses from your lighting sources. Today's sophisticated dimming systems enable you to lower the light level to conserve energy and increase bulb life, vary the mood of a room, alter light source intensity, and create a lighting scene in each room. Types of controls include integrated dimming systems, touch dimmers, slide dimmers, and rotary dimmers. 

Light Pollution

The excessive and misdirected use of artificial lights is known as light pollution. It is a form of environmental pollution that hurts natural cycles and ecosystems, including the disruption of nocturnal wildlife behavior and the reduction of visibility of stars in the night sky.

Lumen

A unit of luminous flux; the overall light output of a luminous source is measured in lumens. Amount of light the lamp emits once it's turned on.

Lumen Depreciation

The decrease in lumen output of a light source over time; every lamp type has a unique lumen depreciation curve (sometimes called lumen maintenance curve) depicting the pattern of decreasing light output.

Luminaire (“Light Fixture”)

A complete lighting unit that consists of a lamp or lamp with the parts designed to distribute the light, position and protect the lamps, and connect the lamps to the power supply. 

RGBW

RGBW is an acronym for Red, Green, Blue, and White, a type of LED lighting technology. It combines red, green, and blue LEDs to create a variety of colors while adding a white LED to the mix for added brightness and more natural light. RGBW lighting is commonly used for home and business lighting applications, stage lighting, architectural lighting designs, and interior design lighting schemes.

Task, Ambient, and Accent Lighting

Lighting design typically incorporates three primary layers:

• Task Lighting: Focused light used for activities such as reading, cooking, or working. Examples include desk lamps, under-cabinet lighting, and pendant lights over kitchen islands.

• Ambient Lighting: General illumination that provides overall brightness to a space. Ceiling-mounted fixtures, chandeliers, and recessed lighting often serve this purpose.

• Accent Lighting: Decorative lighting used to highlight architectural features, artwork, or landscaping. Wall sconces, track lighting, and spotlights fall into this category.

IP Ratings (Ingress Protection)

IP ratings indicate a fixture’s level of protection against dust and moisture. The rating consists of two digits; the first refers to dust resistance (0–6), and the second relates to water resistance (0–8). For example, an IP44-rated fixture is protected against solid objects larger than 1mm and splashing water, making it suitable for bathrooms. Outdoor fixtures typically require IP65 or higher to withstand rain and dust.

Smart Lighting

Smart lighting systems allow users to control brightness, color, and scheduling remotely via smartphones or voice assistants. Many smart bulbs and fixtures integrate with home automation platforms, enabling features like motion activation, scene setting, and energy monitoring. These systems provide both convenience and efficiency, making them a popular choice for modern homes.

Task Light

Lighting that is explicitly designed to help make tasks more accessible, such as reading or writing. It is usually more focused and brighter than general lighting in a room. A desk or floor lamp are some of the more common task lights. 

Watt

Measurement unit for the electric power consumption of lighting fixtures or any other appliance that runs on electricity. 

Lighting Controls

Beyond basic on/off switches, advanced lighting controls include:

• Dimmer Switches: Adjust brightness levels to enhance ambiance and energy savings.

• Motion Sensors: Activate lights upon detecting movement, ideal for security lighting and energy conservation.

• Timers: Program lights to turn on or off at specific times.

• Daylight Sensors: Adjust lighting based on natural light levels to optimize energy efficiency.

Energy Efficiency and LED Technology

LED technology has revolutionized the lighting industry by offering superior energy efficiency, longer lifespan, and reduced maintenance. Compared to incandescent bulbs, LEDs consume up to 80% less energy and can last 25 times longer. Additionally, they generate less heat, making them safer and more environmentally friendly.

Enhancing Your Space with the Right Lighting Choices

Understanding lighting terminology helps homeowners and businesses make informed decisions about their lighting needs. Whether upgrading to energy-efficient LEDs, selecting the right color temperature, or exploring smart lighting options, knowing these terms ensures optimal lighting performance and enhanced comfort. For professional electrical services and expert lighting solutions, always consult a licensed electrician to ensure safety and code compliance.

Thomas Edison Electric is your answer to “Who is the best electrician near me,” and we also happen to have an emergency electrician near you 24x7 that you can count on! Give us a call today!