Bulb label reader
The Lighting Facts label annotated line by line, the lumens that replace the old watts, the color names packages use, color rendering thresholds by publisher, and the package words that matter.
Take this page to the store, or open it beside a bulb box at home. It reads the label and the package fine print; Bulbs, labels and color teaches what each figure means (the label, color temperature, color rendering, flicker). Figures for fictional bulbs are marked as such.
- The Lighting Facts label, line by line
- Lumens for the old watts
- Color temperature names, by publisher
- Color rendering thresholds, by publisher
- Package words and what they mean
- Flicker lines
The Lighting Facts label, line by line
The FTC's Energy Labeling Rule, 16 CFR 305.23, sets what the Lighting Facts panel on the side or back of a bulb package says and in what order. The front of the package repeats the first two lines, brightness and estimated energy cost. The label below is for Marisol's 800-lumen 2700 K bulb from this manual's fictional examples.
Lighting Facts Per bulb (fictional example)
Brightness: 800 lumens
Average initial light output, rounded to the nearest 5 lumens. This is the figure to shop by: it replaced watts as the measure of brightness. The bulb itself also has to be marked with its lumens.
Estimated Yearly Energy Cost: $1.08
Based on the bulb's average initial wattage, 3 hours a day and 11 cents per kWh, as the rule sets. For a 9 W bulb: 9 W × 3 h × 365 ÷ 1,000 = 9.9 kWh, × $0.11 = $1.08. The FTC kept the 11-cent figure in 2024 because the line is for comparing bulbs, not predicting a bill. Your own rate is on your bill; the cost calculator uses it.
Life: 13.7 years
Life in years to the nearest tenth, based on 3 hours a day. The 13.7 here is a fictional figure for this example (about 15,000 hours). For an LED it is a projection of the hours until light output falls to 70 percent, not a promise, and heat in an enclosed fixture shortens it (Bulbs, labels and color, LED life).
Light Appearance: 2700 K, marked on a scale from 2,600 K to 6,600 K
The correlated color temperature in kelvin, with a marker placed on a scale whose left end is 2,600 K and right end 6,600 K. Lower numbers look warmer (more yellow), higher numbers cooler (more blue). It describes the color of the light, not how colors look under it.
Energy Used: 9 watts
Average initial wattage: the bulb's actual watts. Compare this figure, not an "equivalent" wattage on the front of the box, with the maximum-wattage label on the lamp or fixture. NFPA's consumer guidance says to use bulbs that match the fixture's recommended wattage and to read LED labels to be sure the bulb suits the fixture.
Other lines the rule allows or requires in some cases: the ENERGY STAR logo (optional, certified products only), the design voltage if not 120 V, and "Contains Mercury" for bulbs that contain it. A 3-way bulb lists each level's lumens.
What the label leaves out
The rule does not require the label to report color rendering (CRI or R9), flicker, dimmer compatibility or whether the bulb is rated for enclosed fixtures. Those are in the package fine print, if anywhere, and in the maker's specification sheet. Read them from the tables below.
The label compares bulbs. It does not predict your electricity bill (that depends on your rate, your hours and how many bulbs), a lifespan in your fixture (heat, switching and the fixture's design change it), or how colors will look in your room (two bulbs with the same kelvin and CRI can still look different). A trial in the room settles that: Your lighting plan, the bulb trial.
Lumens for the old watts
ENERGY STAR's Learn About Brightness page gives the minimum lumens to replace an old incandescent bulb. ENERGY STAR stopped certifying bulbs at the end of 2024, but this table matches DOE's and remains the common reference. Teaching: Bulbs, labels and color, efficiency.
| Old incandescent bulb | Minimum lumens to replace it |
|---|---|
| 40 W | 450 |
| 60 W | 800 |
| 75 W | 1,100 |
| 100 W | 1,600 |
| 150 W | 2,600 |
Marisol's fictional 800-lumen bulb uses 9 W, about 89 lumens per watt. Since July 25, 2022, federal rules have barred the sale of general service bulbs below 45 lumens per watt.
Color temperature names, by publisher
Package names for color temperature are marketing conventions. The publishers below map names to kelvin figures slightly differently; the kelvin number on the label is the figure to compare. Teaching: Bulbs, labels and color, color temperature.
| Publisher | Warm | Middle | Cool | Notes |
|---|---|---|---|---|
| FTC Lighting Facts label (16 CFR 305.23) | A kelvin figure marked on a scale from 2,600 K (left) to 6,600 K (right) | The rule requires the number and the scale, not a name. | ||
| ENERGY STAR Bulb Purchasing Guide | Warm White or Soft White: 2700 K | Cool White or Neutral White: 3000 to 4100 K | Natural or Daylight: 5000 to 6500 K | An older guide; its room suggestions are conventions, not findings. |
| IES consumer guide Lighting Your Way to Better Vision (a copy hosted by the Center of Design) | 2,700 to 3,000 K | 3,500 K (neutral) | 4,100 to 5,000 K | Derived from IES RP-28-20, since revised as RP-28-25. |
| Former ENERGY STAR lamp specification (Version 2.1) | Allowed nominal values: 2700, 3000, 3500, 4000 or 4100, 5000 and 6500 K | What certified bulbs could be labelled until the program ended on December 31, 2024. | ||
| California JA8 (2025 Reference Appendices) | A nominal color temperature of 4000 K or less | Applies to lighting in new California homes under Title 24; an example, not a national rule. | ||
Color rendering thresholds, by publisher
CRI (Ra) scores how closely a light renders eight test colors compared with a reference; R9 is saturated red, which matters for skin and food. TM-30 is the newer measure: Rf for average fidelity, Rg for gamut (saturation), and Rcs,h1 for the chroma shift of reds. Publishers draw the lines in different places, and DOE's fact sheet notes that "there is no substitute for visual evaluation." Teaching: Bulbs, labels and color, color rendering.
| Publisher | Threshold | What it applies to |
|---|---|---|
| U.S. DOE, LED Basics | CRI 80 minimum recommended for interiors; 90 or higher is excellent fidelity | Interior lighting in general |
| U.S. DOE, LED Color Characteristics (2012) | CRI in the 70s acceptable for interiors, 80s good, 90s excellent; R9 above 0 generally considered acceptable | A rule of thumb on the fact sheet; it warns against comparing CRI across very different color temperatures |
| Former ENERGY STAR lamp specification (Version 2.1) | CRI at least 80, no unit below 75; R9 above 0 for LEDs | Certified bulbs until December 31, 2024 |
| IES consumer guide (copy linked above) | CRI 80 or higher | Lighting for older adults at home |
| California JA8 (2025) | CRI 90 or higher and R9 50 or higher (82 for lamps covered by California's Title 20) | New California homes; marked "JA8-2025" |
| PNNL, Emerging Specification Guidance for TM-30 (2018) | Found no peer-reviewed evidence supporting CRI 80 as a quality line; sources with Rf at least 75, Rg at least 98 and Rcs,h1 from -7 to 15 percent were well accepted in its experiments | A research summary, not a standard |
| TM-30 Annex E, levels set in the 2018 edition (explained in TM-30: The Sequel, 2019) | Preference P1: Rf 78 or more, Rg 95 or more, Rcs,h1 from -1 to 15 percent. P2: Rf 74, Rg 92, -7 to 19 percent. P3: Rf 70, Rg 89, -12 to 23 percent. Fidelity F1: Rf 95; F2: Rf 90 and red fidelity 90; F3: Rf 85 and red fidelity 85 | Typical interior light levels with varied colors. The current edition is TM-30-24; these are the 2018 edition's levels. |
A CRI 90 bulb with a positive R9 is a reasonable screen when color matters, not a promise of how your room will look. Convention
Package words and what they mean
| On the package | What it means | Source |
|---|---|---|
| Dimmable | The bulb is meant to work on a dimmer. Whether it works well on yours depends on the dimmer; look for the dimmer maker's compatibility list or a list on the package. ENERGY STAR's guide says to look for "Dimmable" for a dimmer; the Lighting Facts label does not say. | ENERGY STAR guide; Switches, dimmers and evening light |
| 3-Way | For a 3-way socket (a lamp with three brightness clicks). The label lists each level's lumens, for example 800/1600/2500, and bases life on the shortest-lived level. | ENERGY STAR guide; 16 CFR 305.23 |
| Not for use in totally enclosed luminaires (or fixtures) | The bulb is not meant for a fixture that encloses it, such as a sealed glass dish. Heat builds up in an enclosed fixture and shortens LED life. Use a bulb whose package says it is suitable for enclosed fixtures there. | ENERGY STAR V2.1 |
| Damp location, wet location | Markings on fixtures. A damp location is protected from weather but subject to moderate moisture; a wet location can be saturated or exposed to weather, and wet-rated fixtures are marked "Suitable for Wet Locations". Where a fixture may go near a tub or shower is set by the code your area has adopted, and your electrician and inspector decide it. | H.E. Williams, reprinting the NEC and UL 1598 definitions |
| JA8-2025 (or JA8-2022) | The light source meets California's high-efficacy qualification for that code cycle: CRI 90 and R9 50 or higher, 4000 K or less, dimmable to 10 percent, and reduced flicker. Useful as a shorthand for those figures anywhere. | California JA8 |
| A testing-lab mark (UL, ETL, CSA and others) | A laboratory recognized by OSHA tested and certified the product to one or more product safety standards. UL is not the only valid mark. | OSHA, NRTL program |
| ENERGY STAR logo on a bulb | Older stock: ENERGY STAR stopped certifying bulbs on December 31, 2024. | Bulbs, labels and color |
Flicker lines
Percent flicker is 100 × (maximum − minimum) ÷ (maximum + minimum) of the light's output over one cycle. For most North American light sources that flicker, the frequency is 120 Hz, twice the 60 Hz supply. Packages rarely state flicker; look in the maker's specification sheet. Teaching: Bulbs, labels and color, flicker; the phone test: Survey and test your rooms.
| Line | Limit | At 120 Hz | Source and status |
|---|---|---|---|
| IEEE 1789 low-risk level | Percent flicker no more than frequency × 0.08 (frequency at least 100 Hz) | 10 percent | IEEE Std 1789-2015, a recommended practice, as summarized by its committee chair and PNNL (LightFair 2015 slides) |
| IEEE 1789 no-effect level | Percent flicker no more than frequency × 0.0333 | About 4 percent (our arithmetic) | Same source; offered for sensitive populations |
| California JA8 | Percent flicker under 30 percent at frequencies below 200 Hz, at full and at 20 percent output | Under 30 percent | California JA8 (2025); binding only in California new construction |
Dimmers can create or increase flicker, so a figure measured at full output may not hold when dimmed. A phone's slow-motion video can flag flicker but cannot rule it out. Test it