Not sure what a specification means? This guide separates brightness, color, efficiency, compatibility, and installation so you can compare fixtures with confidence.
At a glance
- Lumens
- How much light
- Watts
- Electricity used
- Kelvin
- Warm or cool appearance
- CRI
- How faithfully colors appear
Lighting glossary
Lumens & brightness
Lumens measure the total amount of visible light a source produces. More lumens generally means more light; watts measure electricity, not brightness.
For a starting estimate, multiply room length by width, then multiply the square footage by the range below. These ranges describe total light in the room, not necessarily one fixture.
- Hallways and soft accent light: 5–10 lumens per sq. ft.
- Living rooms and bedrooms: 10–20 lumens per sq. ft.
- Dining rooms and general kitchen light: 30–40 lumens per sq. ft.
Estimate total room lumens
Use this as a planning starting point.
Ceiling height, dark finishes, shades, diffusers, beam direction, and layered lighting can change what feels right.
Color temperature, Kelvin & CCT
Kelvin (K) describes the appearance of white light, not its brightness. Lower numbers look warmer and more amber; higher numbers look cooler and bluer. CCT means correlated color temperature.
2200–2700K feels candlelike to warm; 3000K is warm and clean; 3500K is neutral; 4000K is crisp neutral; and 5000–6500K resembles cool daylight.
Names such as warm white and daylight vary by manufacturer. Two lights can have the same Kelvin value but different lumen output.
CRI (Color Rendering Index)
CRI describes how faithfully colors appear compared with a reference light of the same color temperature. It does not tell you brightness or how warm the light looks.
A CRI of 80+ is common for general use. A CRI of 90+ can be helpful where skin tones, art, wood, fabric, and finish colors matter. Two lights with the same CRI can still render individual colors differently.
Integrated LED
The LED light source is built into the fixture rather than supplied as a standard replaceable bulb. You normally do not need to buy separate bulbs. Whether the LED module or driver can be serviced or replaced depends on the exact product.
Rated LED life is an estimate of light-output maintenance and is not the same as the product warranty.
Bulb bases & replaceable bulbs
The base code identifies how a bulb connects to the socket. E12 is a small candelabra screw base, E26 is the common medium screw base, GU10 is a twist-lock base, and G9 is a compact bi-pin base.
Match the exact base, bulb shape, voltage, and maximum wattage shown for the fixture. A compatible base alone does not guarantee the bulb will physically fit.
Wattage
Watts measure electrical power. For an integrated LED, input wattage helps estimate energy use. For a socketed fixture, a maximum such as 60W each is a safety limit per socket—not a brightness recommendation. Never exceed it.
Efficacy (lumens per watt)
Efficacy compares light output with power use. A higher lm/W number means the source produces more lumens for each watt. It measures efficiency, not total brightness, color temperature, or color quality.
Dimming & compatible controls
A replaceable-bulb fixture normally needs dimmable bulbs and a compatible dimmer, and the fixture must support that setup. An integrated LED listed as dimmable is designed to dim, but the manufacturer may still specify an approved control type and minimum dim level. TRIAC, ELV, MLV, and 0–10V are different control methods and are not automatically interchangeable.
Dimmable: Yes does not mean a dimmer switch is included.
Selectable CCT & tunable white
Selectable CCT offers preset white-light temperatures, often chosen with a switch on the fixture or driver. Tunable white may allow a broader adjustable range. Neither term automatically means the setting can be changed from an app, remote, or wall switch after installation.
RGB + CCT
RGB channels create colored light, while CCT channels create adjustable shades of white light. The control method—such as an app, remote, or compatible wall control—must be stated for the individual product.
Beam angle
Beam angle describes how widely light spreads. A narrow beam is more focused and can feel more intense; a wide beam covers a broader area. The mounting distance also changes the size and brightness of the lit area.
Rated LED life
Rated life is an estimate of operating time before an LED reaches a defined level of light-output depreciation, often about 70% of its initial output. It is not an exact failure date.
Heat, operating conditions, and usage can affect actual life. Rated life is not the same as warranty length.
LED driver
An LED driver converts and regulates electrical power for the LED. It may be built into the fixture or installed separately. Its voltage and dimming compatibility can affect performance.
Dry, damp & wet location ratings
Dry-rated fixtures are for normally dry interiors. Damp-rated fixtures can handle moisture or condensation in protected areas but not direct water. Wet-rated fixtures are designed for direct weather or water exposure when installed as instructed.
Always follow the exact location listing and installation instructions for the product.
IP rating
An IP code uses two digits: the first describes protection from solid objects and dust, and the second describes protection from water. A higher digit means more protection within that category.
An IP rating does not automatically replace any electrical or wet-location listing required for the installation.
UL, ETL & safety listings
UL Listed and ETL Listed indicate that a product was evaluated by an independent testing laboratory to applicable safety standards. Marks that include c, us, or cETLus indicate Canadian, U.S., or combined coverage. A listing is not a performance score or warranty.
Voltage
The fixture or driver voltage must match the power supply. Many U.S. residential hardwired fixtures use 120V, while low-voltage and universal-input products differ. Use only the voltage range stated for the product.
Hardwired vs. plug-in
A hardwired fixture connects to the building wiring, usually at an electrical junction box. A plug-in fixture uses a power cord and wall outlet.
A cord, cable, chain, or downrod length on a hardwired pendant describes how it hangs; it does not make the fixture plug-in.
Adjustable hanging height
The useful specification states the minimum and maximum installed height. Check whether the range refers to overall fixture height or only the cord, chain, or downrod, and whether it includes the canopy and fixture body.