How to read a light bulb label: lumens, kelvin, CRI and flicker
The Lighting Facts label line by line, what it leaves out, and how to choose a bulb by brightness, color and color rendering rather than by watts.
- Start here: the essentials
- 1. The Lighting Facts label
- 2. Color temperature: kelvin
- 3. Color rendering: CRI, R9 and TM-30
- 4. Efficiency, the federal rules and running cost
- 5. LED life and heat
- 6. Flicker
- 7. Blue light and your eyes
- 8. See it: Marisol's two ceiling bulbs
- 9. Practice: read every bulb in one room
- 10. Your rooms
- 11. Check your work
- 12. Knowledge check and scenario
Start here Essentials
At minimum, read the bulbs in your first room, write down what they are, and choose one bulb to try. Everything marked Go deeper can wait.
- Read one bulb and its box. Light off, bulb cool; read the base and the package (the label).
- Write each bulb's lumens and kelvin. Add the CRI if it is printed, on the fixtures sheet (kelvin, CRI).
- Check the fixture's wattage label. Note its maximum watts and whether it is enclosed (heat).
- Pick the bulb to try. One kelvin and one lumen figure for the room's main light, written in the plan.
Minimum time: about 20 minutes. Done when: the fixtures sheet has one row per bulb in your first room with lumens and kelvin, and the plan names the bulb to try.
1. The Lighting Facts label Understand
Every general-purpose bulb sold in the US carries a Lighting Facts label, a panel the Federal Trade Commission requires on the side or back of the package. The rule (16 CFR 305.23) sets what it shows and in what order (FTC Energy Labeling Rule, 16 CFR 305.23). The front of the package must also show the brightness and the yearly energy cost, equally prominent, and the bulb itself must be marked with its lumens. Convention
| Label line | What it reports | How to read it |
|---|---|---|
| Brightness | Average initial light output in lumens, rounded to the nearest 5 | The number to compare. The table in How light works in a room translates old incandescent watts. |
| Estimated Yearly Energy Cost | Dollars a year at 3 hours a day and 11 cents per kilowatt-hour | For comparing bulbs, not for predicting a bill (see running cost). |
| Life | Years, to the nearest tenth, at 3 hours a day | A projection, not a promise (see LED life). |
| Light Appearance | Correlated color temperature in kelvin, marked on a scale from 2,600 K (warm) to 6,600 K (cool) | The color of the light itself (see kelvin). |
| Energy Used | Average initial power in watts | The watts the bulb draws. Compare it with the fixture's maximum. |
| Contains Mercury | Only for bulbs with mercury (fluorescent types) | Disposal information follows it. |
A 3-way bulb lists each level, for example 800/1600/2500 lumens. The ENERGY STAR logo is optional and, since the end of 2024, no longer issued for bulbs (see efficiency).
What the label leaves out
The FTC rule does not require the label to report color rendering (CRI), flicker or dimmer compatibility. Those, and the enclosed-fixture warning, sit in the package fine print or in the maker's specification sheet, the technical page most bulb makers post for each model. Product-specific ENERGY STAR's old purchasing checklist told shoppers to look for "Dimmable" on the package for a dimmer and "3-Way" for a 3-way socket, and to check with the control's maker before using a bulb with a photocell, motion sensor or timer (ENERGY STAR, Bulb Purchasing Guide). That advice still holds; the checklist's wattage column dates from compact fluorescents and is out of date for LEDs.
Watts: the fixture's label and the bulb's
Turn the light off and let the bulb cool before you take it out. Use a bulb whose watts are within the fixture's label. If the fixture is enclosed (a closed glass dish or globe), use a bulb whose package says it is suitable for enclosed fixtures. If a fixture has no wattage label, the Consumer Product Safety Commission advises a bulb of 60 watts or less, and 25 watts for fixtures that take miniature bulbs (CPSC, Home Electrical Safety Checklist). A switch or outlet plate that is hot or discolored, buzzing, a burning smell, sparks, lights that flicker or dim when appliances start, or a breaker that trips repeatedly: stop using it and call a licensed electrician.
Most fixtures carry a small label inside the shade or canopy, such as "max 60 W". The CPSC checklist explains why it matters: a bulb of higher wattage than recommended may overheat the fixture, the wiring or things nearby. The National Fire Protection Association's consumer guidance says to use bulbs that match the wattage recommended on the lamp or fixture and, for LED replacements, to read the labels to make sure the bulb suits that fixture and location (NFPA, Educational Messages Desk Reference, 2026). Convention
Two wattages appear on an LED package. The label's Energy Used line is the power the bulb draws. The front often also says "60 W equivalent": ENERGY STAR describes that as the standard incandescent wattage the bulb is meant to replace in brightness. When you compare a bulb with the fixture's maximum, the Energy Used line is the bulb's own wattage. Product-specific An 800-lumen LED drawing about 9 watts sits well within a 60-watt fixture label; the enclosed-fixture question is separate and depends on the bulb's package.
2. Color temperature: kelvin
Correlated color temperature (CCT), given in kelvin (K), describes the color of the light itself: lower numbers look yellower and warmer, higher numbers bluer and cooler. The Department of Energy's fact sheet on LED color defines it by comparison with a heated object that glows at that temperature, and stresses that CCT describes the light's color, not how objects look under it (DOE, LED Color Characteristics). Physical principle
Packages attach names to kelvin ranges. ENERGY STAR's checklist used these:
| Package name | Kelvin | What it looks like |
|---|---|---|
| Warm white, soft white | 2700 K | The color of an ordinary incandescent bulb; yellowish white |
| Cool white, neutral white | 3000 to 4100 K | Whiter; the checklist shows 3000, 3500 and 4100 K |
| Natural, daylight | 5000 to 6500 K | Bluish white |
The names are marketing conventions, and so are the room labels the checklist printed beside them ("good for kitchens", "good for reading"). No research finding says a kitchen needs 4000 K or a bedroom 2700 K. Convention Published guidance leans warm for homes: the Defense Department's housing criteria recommend 2700 K for residential spaces and no interior source above 4100 K, and the IES consumer guide for older adults calls 2,700 to 3,000 K warm and suggests low, warm light in the evening. Those are conventions too. The practical method is to try two kelvins in the room, at the hour you use it. Test it
Why two bulbs of the same kelvin can still differ
Kelvin is one number for a color that can still lean slightly green or slightly pink. The DOE fact sheet calls that lean Duv: a measure of how far the light sits above (greenish) or below (pinkish) the line of colors a glowing object produces. Two bulbs at 2700 K from different makers can look different side by side for this reason. Packages rarely print Duv; your eyes, with the two bulbs side by side, are the test.
Mixing kelvins in one room
ENERGY STAR's 2023 consumer messages said to choose the same light-appearance number for the bulbs or fixtures in one room (ENERGY STAR, Lighting Products 2023 Key Messages). Convention A 2700 K and a 5000 K bulb in the same fixture make a white wall look two colors and make one half of the room look cold. Matching kelvin, and buying the bulbs for one room from one product line where you can, is the simplest fix for the "colors don't match" problem.
Kelvin also changes how paint looks. Our manual on observing light for paint color, Learn Color Design's Observe your light, shows how the same chip shifts between daylight and bulbs of different kelvin, and is worth reading before you repaint a room you are also relighting.
3. Color rendering: CRI, R9 and TM-30
Kelvin says what color the light is. Color rendering says how faithfully objects look under it compared with a reference light of the same color temperature. A bulb can be a pleasant 2700 K and still make red fabric look brownish and skin look sallow.
CRI and R9
The color rendering index (CRI, written Ra) averages how closely eight standard color samples match their appearance under the reference light; 100 means identical. The DOE fact sheet explains its limits: the eight samples leave out saturated colors such as a deep red, two bulbs with the same CRI can still render colors differently, and CRI should not be compared across very different color temperatures. R9 is a separate score for a saturated red, which matters for skin, wood and food; the fact sheet calls R9 above 0 generally acceptable. Convention
Publishers set the "good enough" line in different places:
| Publisher | Threshold | Status |
|---|---|---|
| DOE, LED Basics | CRI 80 minimum for interiors; 90 or higher is excellent fidelity | Current DOE guidance (DOE, LED Basics) |
| DOE, LED Color Characteristics | 70s acceptable for interiors, 80s good, 90s excellent; R9 above 0 acceptable | 2012 fact sheet; a rule of thumb |
| ENERGY STAR Lamps V2.1 | CRI at least 80, R9 above 0 | What certified bulbs met until the program ended in 2024 (ENERGY STAR Lamps V2.1) |
| California JA8 (2025) | CRI at least 90, R9 at least 50 (82 for lamps covered by California's Title 20) | Binding for certain lighting in new California homes (California Energy Commission, JA8) |
| Defense Department housing criteria | CRI 80 or higher; kitchens CRI 90 or higher with a minimum R9, or a TM-30 alternative | Design criteria for military housing |
California appears here as an example of one state's rule; it binds builders there, not your choice of bulb.
Behind the numbers sits a finding that should temper any threshold. A Pacific Northwest National Laboratory review found that no peer-reviewed experiment supports CRI 80 as a line that ensures acceptable color, that the line began as the boundary between two generations of fluorescent tubes, and that many of the light sources people liked best in studies had CRIs in the low 70s (Royer, Emerging Specification Guidance for TM-30, PNNL). A CRI of 90 with a positive R9 is a reasonable screen when shopping; it is not a guarantee that colors will look right to you. The DOE fact sheet's own conclusion is that nothing replaces looking. Test it
TM-30
TM-30 is the Illuminating Engineering Society's newer method. It scores 99 color samples and reports two main numbers: Rf, average fidelity (like CRI, 0 to 100), and Rg, the gamut index, which says whether colors look more saturated (above 100) or duller (below 100) on average. It also reports shifts by hue, so a sheet can show that reds are pushed toward vivid or toward dull. DOE lists the current edition as TM-30-24 (DOE, TM-30 Frequently Asked Questions). Few household bulb boxes print TM-30 values; some specification sheets do.
CRI and TM-30 thresholds differ by publisher, and none was written for one person choosing a bulb for one room. A number on the box narrows the choice; it does not tell you how your walls, your skin or your sofa will look. Try the bulb in the room at the hour you use it, beside a white sheet of paper, a red object and your own hand, and record what you see in the tests sheet. If you are choosing paint at the same time, Learn Color Design's Observe your light (this manual on observing light for paint color) shows how to look.
TM-30 levels, as the 2018 edition's annex set them
PNNL's 2019 article on TM-30 decodes the specification levels in the 2018 edition's Annex E, meant for typical interior light levels of about 200 to 700 lux (Royer, TM-30: The Sequel, PNNL). We have not confirmed them against the current TM-30-24, so read them as the 2018 levels.
| Aim | Level 1 (strictest) | Level 2 | Level 3 |
|---|---|---|---|
| Preference | Rf ≥ 78, Rg ≥ 95, red chroma shift −1% to 15% | Rf ≥ 74, Rg ≥ 92, −7% to 19% | Rf ≥ 70, Rg ≥ 89, −12% to 23% |
| Vividness | Rg ≥ 118, red chroma shift ≥ 15% | Rg ≥ 110, ≥ 6% | Rg ≥ 100, ≥ 0% |
| Fidelity | Rf ≥ 95 | Rf ≥ 90, red fidelity ≥ 90 | Rf ≥ 85, red fidelity ≥ 85 |
A positive red chroma shift means reds look slightly more vivid than under the reference. The article notes that the strictest preference, vividness and fidelity levels together are not achievable in one source. For a home, the preference row is the one that matches the PNNL finding that people tend to like slightly saturated reds.
JA8 marks
Bulbs certified to California's JA8 carry a "JA8-2022" or "JA8-2025" mark. The mark is a shorthand for a bundle of requirements: CRI 90 and R9 50 (for most sources), 4000 K or below, dimmable to 10 percent, a flicker limit and a noise limit. Outside California it is a useful sign that a bulb was tested for those things, not a legal requirement.
4. Efficiency, the federal rules and running cost
Efficacy is light out per power in, in lumens per watt (lm/W). An 800-lumen LED that draws 9 watts has an efficacy of about 89 lm/W; a 60-watt incandescent giving the same 800 lumens, about 13. Physical principle DOE's LED Basics page says LED efficacy can reach about 150 lm/W in some products.
What the federal rules require
Since July 25, 2022, federal rules prohibit the sale of any general service lamp (the ordinary household bulb, in the rule's definition) that does not reach 45 lumens per watt (10 CFR 430.32(dd)). Ordinary incandescent and halogen household bulbs cannot reach that level, which is why they left store shelves. The floor is a "backstop" Congress wrote into law in 2007, which DOE put into effect with a 2022 rule (DOE, Backstop Requirement for General Service Lamps, 2022). Bulbs you already own are not affected, and several specialty types fall outside the definition. Convention
A 2024 DOE rule sets higher levels for bulbs made or imported from July 25, 2028. For a common A-shape LED at about 800 lumens, the level works out to about 124 lumens per watt; the rule's own table gives 124.6 lm/W at 810 lumens, and 115.7 for a bulb with standby power such as a smart bulb (DOE, Energy Conservation Standards for General Service Lamps, 2024). The rule applies to manufacture and import dates, not to bulbs already sold or in your home.
Federal efficiency rules are politically contested, so we state what is in force on the date we checked. On 2026-10-14 the codified rule still carried the 2028 levels (its latest version is dated 2025-05-20), and a search of the Federal Register found no DOE action after that date delaying or withdrawing them. The next yearly review of this manual re-checks it.
ENERGY STAR no longer certifies bulbs
EPA ended the ENERGY STAR specifications for bulbs and most fixtures on December 31, 2024; only recessed downlights kept a specification (EPA, ENERGY STAR lighting sunset memo; ENERGY STAR, Light Fixtures for Partners). EPA's reason was that the 45 lm/W floor already secured the efficiency gains. A bulb with an ENERGY STAR mark on a shelf now is old stock, and older advice that says "look for ENERGY STAR bulbs" is out of date. The Lighting Facts label and the fine print are the guides.
Running cost
The label's yearly cost uses 3 hours a day and 11 cents per kilowatt-hour. The FTC proposed in 2024 to leave that figure alone, reasoning that the label mainly helps shoppers compare similar bulbs, not predict a bill (FTC, Energy Labeling Rule proposal, 2024). Your own cost needs your own rate and hours:
cost a year = watts × hours a day × 365 ÷ 1,000 × your rate per kWh
For a 9-watt LED on 3 hours a day: 9 × 3 × 365 ÷ 1,000 = 9.9 kWh a year, which is $1.08 at 11 cents. For a 60-watt incandescent on the same hours: 65.7 kWh, $7.23. The running-cost calculator does the sum with your rate from a bill. You may see larger figures quoted, such as DOE's 2021 estimate that an average household saves about $225 a year with LEDs; that is a national average across all of a household's bulbs, not a figure for your home.
The 2028 equation in plain words
The 2028 level is not one number. For the common A-shape LED without standby power, the rule computes it from the bulb's lumens: 123 divided by (1.2 plus e raised to −0.005 × (lumens − 200)), plus 25.9. In words: low-lumen bulbs get a lower bar, and from about 800 lumens upward the bar levels off near 128 lm/W. At 450 lumens it is about 109; at 800, about 124; at 1,600, about 128. The running-cost calculator shows the level for the lumens you enter. Color-tunable bulbs and some smart bulbs with extra functions, sold in packs of two or fewer, are exempt from the 2028 levels.
The cost arithmetic at your own rate
Change one input at a time. At 17 cents per kWh the 9-watt LED costs $1.68 a year at 3 hours a day; at 6 hours a day, twice that. The point of the arithmetic is the comparison: across the bulbs in one room, the difference between two LEDs of similar efficacy is cents a year, so color, rendering and flicker usually matter more to the choice than efficacy does.
5. LED life and heat
The lifetime guide cited below notes that an LED's end of life may not be obvious: it may dim slowly rather than go out. That changes what "life" means. DOE's LED Basics page defines useful life as the hours until the light falls to 70 percent of its initial output, called L70, and says good-quality white LED products are expected to reach 30,000 to 50,000 hours or more, against about 1,000 hours for a typical incandescent. Product-specific
The industry's lifetime guide, written with DOE, recommends a stricter default, B50/L70: the time by which half of a population of the product has fallen below 70 percent of its initial output for any reason, including a failed driver (LED Luminaire Lifetime: Recommendations for Testing and Reporting, 2014). Both are projections from tests much shorter than the claimed life. The label's "Life" in years divides the projected hours by 3 hours a day, so "13.7 years" means "about 15,000 hours", and a lamp used 6 hours a day reaches it in about half the years.
Heat and enclosed fixtures
The lifetime guide explains that LEDs do not radiate their heat away: it has to leave by conduction and air movement, and higher temperature speeds the decline of the LED and its electronics. A bulb sealed in a glass dish or globe runs hotter. That is why some packages say "not for use in totally enclosed luminaires"; ENERGY STAR's specification required that kind of exception to be stated on the package, and tested bulbs without it at a raised temperature. Product-specific If bulbs in one enclosed fixture keep failing early, check the package for an enclosed-fixture statement before blaming the brand.
6. Flicker
Lights that flicker or dim when other appliances switch on, or flickering that a new bulb does not fix, can be a wiring problem rather than a bulb problem. NFPA lists flickering lights among the signs to call a licensed electrician. Stop using that light and call one.
Light from a bulb on household alternating current can rise and fall many times a second; for most North American sources the basic rate is 120 times a second, as PNNL's study of handheld flicker meters notes (PNNL, Characterizing Photometric Flicker: Handheld Meters). That variation is called flicker, or temporal light modulation. In an LED it depends on the driver, the electronics inside the base; PNNL's flicker slides list LEDs with cheap drivers among the products more likely to flicker. Most of it is too fast to see directly, but some people notice it, and it can show as a stroboscopic effect, where a moving object such as a mixer blade looks stopped or stepped.
How flicker is measured
Percent flicker compares the highest and lowest light output in each cycle, from 0 (steady) to 100 (fully off between pulses). PNNL's summary of the IEEE 1789 recommended practice, presented by its committee chair, explains the low-risk line: at 120 Hz, percent flicker of about 10 percent or less, and the same 10 percent where the frequency is unknown (Miller and Lehman, Flicker: Understanding the New IEEE Recommended Practice). Convention California's JA8 sets a looser legal limit for the products it covers: under 30 percent at frequencies below 200 Hz, at both full and 20 percent output. We found no federal flicker limit for household bulbs: ENERGY STAR only required makers to report flicker measurements, and the Lighting Facts label does not show them.
Why dimmers make it worse
The PNNL slides list LEDs on phase-cut (wall) dimmers among the products more likely to flicker, and note that a dimmer can introduce or increase it. The European Commission's scientific committee on health risks (SCHEER) says the same: a dimmer may introduce modulation into a lamp that does not flicker at full power (SCHEER, Opinion on Light Emitting Diodes, 2018). Flicker at a low dimmer setting is the most common case at home. Switches, dimmers and evening light covers dimmer compatibility.
What flicker does to people
ICNIRP, as summarized by Australia's radiation protection agency, says the only strong evidence of hazard from LEDs concerns temporal light effects such as flicker. SCHEER found that a small number of people report migraine or headaches from it, and that consumers cannot tell at the store which lamps flicker. On photosensitive epilepsy, SCHEER notes that peak sensitivity is around 20 Hz and that mains-frequency flicker (100 Hz in Europe) is above the frequency of concern. If light or flicker gives you headaches or eye pain, see a doctor; this manual does not give medical advice. Ask the authority
The practical steps are a bulb whose specification sheet reports low flicker or states flicker performance, a bulb on the dimmer maker's compatibility list where there is a dimmer, and the slow-motion phone check in Survey and test your rooms, which can flag flicker but cannot rule it out. In this manual's fictional cases, Noor's bedroom light (fictional) shows banding at the lowest dimmer settings; Switches, dimmers and evening light follows what she tries.
Flicker index and IEEE 1789's two lines
Percent flicker ignores the shape of the waveform. The flicker index, from 0 to 1, compares the area of the waveform above its average with the total, so it accounts for shape and duty cycle but not frequency. IEEE 1789 links the acceptable depth to frequency. For low risk, the slides give percent flicker no more than 0.08 times the frequency (so 9.6, rounded to about 10, at 120 Hz), with no limit at 1,250 Hz and above. For a "no observable effect" level aimed at sensitive groups, the line is 0.0333 times the frequency, about 4 percent at 120 Hz. Some secondary sources quote the stricter line as the general limit; the committee's slides give 0.08 for the general case.
7. Blue light and your eyes
LED bulbs and screens are often said to harm the eyes because of their blue light. This section reports what the bodies that study it found, and where they disagree. It is not eye-health advice: changes in your vision, eye pain or new sensitivity to light are for an eye doctor.
What "blue light hazard" means
The CIE uses blue light hazard for one thing only: photochemical damage to the retina, usually from staring at a very bright source such as the sun or a welding arc (CIE Position Statement on the Blue Light Hazard, 2019). The CIE says the term should not be used for effects on sleep or the body clock, which are a separate question; Switches, dimmers and evening light covers evening light.
Light sources are sorted into risk groups under the photobiological safety standard IEC 62471. DOE's 2013 fact sheet explains them: RG0 (exempt) poses no hazard; RG1 (low risk) is limited by normal behavior, since people do not stare at lights for long; RG2 (moderate) is limited by the natural aversion to bright light and carries a "do not stare" caution; RG3 (high) is a risk from a momentary glance, which DOE calls very unlikely for white light (DOE, Optical Safety of LEDs, 2013 fact sheet). The same fact sheet says LED products are no more hazardous than other lighting at the same color temperature, because blue content follows CCT whatever the technology. Physical principle
What the bodies found
| Body | Finding on retinal harm from white home lighting and screens | Caveats it adds |
|---|---|---|
| CIE (standards body), 2019 | The blue light hazard is not an issue for white general lighting used normally; at similar CCT, LED and incandescent lamps are similar | Blue-only sources can dazzle children; claims linking blue light to macular degeneration are speculative |
| DOE, 2013 | Assessed where a source gives 500 lux, no white source is hazardous; LEDs are no more hazardous than other sources at the same CCT | Infants near bright sources and people with certain eye disease need more care |
| SCHEER (European Commission), 2018 | No evidence of direct adverse effects from LEDs in normal use by the healthy general population | Children are more sensitive to blue light; blue LEDs in toys are a concern; evening light may affect body rhythms |
| ICNIRP, 2020 (as summarized by ARPANSA) | LED lighting installed to good practice poses no more risk of eye damage than traditional sources | Long-term effects of blue-rich LEDs are not fully known; children and older people may be more sensitive |
| American Academy of Ophthalmology, 2021 | No scientific evidence that blue light from digital devices damages the eye | Does not recommend blue-light-blocking glasses for computer use; late screens can delay sleep |
| ANSES (France), 2019 | Warm-white home LEDs carry a low risk of phototoxicity, similar to traditional lighting | Considers blue light toxic to the retina and says chronic exposure raises the risk of macular degeneration; recommends warm white below 3,000 K at home and limiting blue-rich screens at night, especially for children |
Sources for the table: the CIE statement and DOE fact sheet above; SCHEER's opinion; ICNIRP's statement as summarized by Australia's radiation protection agency (ARPANSA, ICNIRP statement on LEDs); the AAO's public page (AAO, Should You Be Worried About Blue Light?); and ANSES's recommendations (ANSES, LEDs: recommendations for limiting exposure to blue light).
Five bodies found no evidence that white home lighting or screens in normal use harm healthy eyes. ANSES is more cautious about long-term exposure, and its own home advice is warm white below 3,000 K. The bodies agree on two narrower points: sources that emit mainly blue light, such as some indicator lights and toys, deserve care around young children, and staring into a bright source from close range is to be avoided. Convention
This section reports what scientific and public-health bodies found about retinal harm; it does not tell you whether your eyes, or a child's, are at risk, and it does not recommend eyewear. Eye discomfort, a change in vision or new sensitivity to light is a question for an eye doctor. Ask the authority Sleep and evening light are a separate question, covered in Switches, dimmers and evening light.
8. See it: Marisol's two ceiling bulbs See it
Marisol Ortega rents; her first room is a 12 by 14 ft living room (How light works in a room). Her complaint is that the colors do not match between lights. Readings, dates and prices in this manual's examples are invented.
Known, from reading the bulbs. The ceiling flush-mount holds two 800-lumen LEDs. One says 2700 K; its CRI is not printed. The other says 5000 K, CRI 80. The fixture's label inside the glass dish says 60 W maximum, and the dish closes around the bulbs, so the fixture is enclosed. The floor lamp has a 450-lumen 2700 K bulb. She writes three rows on the fixtures sheet.
What the label explains. The mismatch is the 5000 K bulb: a bluish-white half next to a yellowish-white half in one dish. Each bulb draws about 9 watts, well within the 60-watt label. At the label's basis, each costs $1.08 a year (9.9 kWh at 11 cents); at the 17 cents on her bill, $1.68. Each gives about 89 lumens per watt, twice the federal floor of 45 and below the roughly 124 the 2028 level sets for new bulbs of this kind. An old 60-watt incandescent giving the same light would cost $7.23 a year at 11 cents and give about 13 lumens per watt.
Her choice to try. An 800-lumen 2700 K bulb with CRI 90, to replace the 5000 K bulb and match the other. She writes it in the plan's general-light row.
Open, and who settles it. Whether the replacement bulb is marked for enclosed fixtures: the package or the maker's specification sheet, read before she buys. Whether CRI 90 looks better to her than the unmarked bulb beside it: her own eyes, in the room, during the trial in Your lighting plan. Whether either bulb flickers: her phone's slow-motion check in Survey and test your rooms, which can flag flicker but not rule it out.
- 16 CFR 305.23: the rule text that sets each label line, with the 11-cent and 3-hour basis. Here so you can check a package against the rule yourself.
- DOE, LED Color Characteristics: a four-page fact sheet with diagrams of CCT, Duv and the CRI samples.
- Learn Color Design, Observe your light: this manual on observing light for paint color, for anyone choosing bulbs and paint together.
9. Practice: read every bulb in one room Practice
Minimum: read each bulb in your first room, write its lumens and kelvin on the fixtures sheet, check the fixture's wattage label, and name one bulb to try in the plan. Time: about 30 minutes. Materials: a step stool if a fixture is overhead, a phone camera to photograph small print, the bulbs' boxes if you kept them.
- Switch off and wait. Turn each light off and give the bulbs a few minutes to cool. Use a stable step stool for a ceiling fixture.
- Read each bulb. The lumens are printed on the bulb. Kelvin, watts and sometimes CRI are on the base or the glass; photograph small print and zoom in. If you kept the box, read its Lighting Facts label and fine print instead, using the label reader.
- Write each bulb on the fixtures sheet. One row per bulb on the fixtures sheet: lumens, kelvin, CRI (or "not printed"), dimmable, the fixture's maximum watts and whether it is enclosed.
- Look for the mismatch. If kelvins differ within the room, note which bulb is the odd one out.
- Name the bulb to try. In the plan, write one kelvin, one lumen figure and a CRI to look for in the room's general-light row. Match the kelvin you like best among the bulbs you already have, unless you have reason to try another.
- Find one specification sheet. Search the maker's site for the model number and look for CRI, R9, TM-30 values, a flicker statement, a dimmer compatibility list and an enclosed-fixture rating.
- Price the running cost. Enter each bulb's watts and lumens, with your rate from a bill, in the running-cost calculator.
- Check for recalls. Search the CPSC's recalls database for any lamp you bought secondhand.
10. Your rooms Your rooms
11. Check your work Check your work
Criteria
- Does every bulb in your first room have a row with lumens and kelvin, and CRI where printed?
- Is each bulb's actual wattage within its fixture's label, and is any enclosed fixture noted?
- If kelvins differ within the room, have you named the odd one out?
- Does the plan name one bulb to try for the room's main light, by lumens, kelvin and CRI, rather than by brand or "equivalent" watts?
- Can you say what the label's yearly cost assumes?
Worked example
Fictional example. Marisol's fixtures sheet has three rows: two ceiling bulbs (800 lumens; 2700 K, CRI not printed; 5000 K, CRI 80; fixture 60 W maximum, enclosed) and the floor lamp (450 lumens, 2700 K). The 5000 K bulb is marked as the mismatch. Her plan names an 800-lumen 2700 K CRI 90 bulb for the ceiling. That meets the criteria. Still open: the enclosed-fixture marking on the bulb she buys, and whether the room has enough light overall (Layers, fixtures and glare).
Common mistakes
- Buying by "equivalent" watts and ending up with a different brightness than the bulb it replaces. Compare lumens.
- Comparing the "60 W equivalent" figure with the fixture's maximum. The Energy Used line is the bulb's own wattage.
- Reading the label's yearly cost as your bill.
- Choosing a kelvin from the room name on the package ("kitchen", "bedroom") rather than from what you see in the room.
- Treating CRI 90 as proof that colors will look right. Look at them.
- Putting a bulb marked "not for use in totally enclosed luminaires" in a closed glass dish.
What is still unresolved
Whether the bulb you choose looks right and stays steady in your room: the trial in Your lighting plan and the flicker check in Survey and test your rooms. Whether it works on a dimmer: Switches, dimmers and evening light. How much light the room needs in all: Layers, fixtures and glare.