Your room-by-room lighting plan: try, retest and file it
The plan assembled from your sheets, a bulb trial in the rooms at the hours you use them, a retest in the same spots, the work put in order, and a binder you keep.
Start here Essentials
At minimum, finish the first room: check its plan rows, try one bulb, take the readings again where you took them in Survey and test your rooms, and save the binder. Everything marked Go deeper is optional on a first pass.
- Check the plan rows. Open the layers sheet and confirm the first room has a row for each layer, with a lamp or fixture, a kelvin figure and a control (assemble the plan).
- Try one bulb in place. Buy the bulb your plan names where the store takes returns, use it for a week at the hours you use the room, and write keep or return in the trial sheet (the bulb trial).
- Retest the same spots. After dark, with the same phone or meter, take three readings at each spot from your first test and mark them "after" in the tests sheet (the retest).
- Export the binder. Save the file from the binder page (the binder).
Minimum time: about an hour of work spread over a week, most of it living with the trial bulb. Done when: the tests sheet shows a before and an after for the first room, the trial sheet has a keep-or-return decision, and the binder file is saved.
1. Assemble the plan from your sheets Understand
By this chapter the plan exists in pieces. Survey and test your rooms left a room survey and the first testing notes, Bulbs, labels and color the fixtures sheet, Layers, fixtures and glare, Switches, dimmers and evening light, Kitchens, bathrooms and desks and Living rooms, bedrooms and stairs the rows of the layers sheet, and Working with an electrician sorted those rows into your work and an electrician's. Assembling the plan means reading the sheets together, room by room, and filling the gaps.
The plan, in this manual, is the set of rows in the layers sheet for every room you chose. A finished row answers six questions for one layer: what it lights (the sofa arm, the counter, the stair treads), with what lamp or fixture and bulb, how much light (a lumen range from the lumen calculator for a general layer, a bulb and a distance for a task layer), what color (kelvin, and CRI where color matters), switched how, and who does it and when.
Each row also carries one of the three statuses from Survey and test your rooms. A row is confirmed when a trial and a retest in that room support it, provisional when it rests on the calculator, a convention or one observation, and unresolved when it waits on someone else's answer: the landlord, the electrician, an eye doctor.
Then read the problems you listed at setup beside the plan. Each problem should point to at least one row. "Too dark" points to a general or task row with a lumen figure; "colors don't match" to one kelvin figure across the room; "a dark path at night" to a night row. A problem with no row is the most common gap in a plan, and it shows as soon as the two lists sit side by side. The check also runs the other way: a row that answers no problem and no activity can go. One lamp can serve two layers.
A whole-home plan with consistent color
With more than one room planned, read the kelvin column down the whole sheet. Rooms that open into each other show their color side by side: a 2700 K living room seen through a doorway into a 5000 K hall looks orange on one side and blue on the other, the same mismatch Bulbs, labels and color found inside one fixture. Many households keep one kelvin figure for the rooms they live in and a cooler one only where a task asks for it. That is a Preference; no source we read sets one figure for a home. Stand in each doorway after dark with both rooms lit and look.
For a household with someone 65 or older, read the lumen column across connected rooms too. The IES consumer guide Lighting Your Way to Better Vision (derived from IES RP-28-20, since revised as RP-28-25) asks for uniform light within and between rooms, because older eyes take longer to adapt. Convention For someone with low vision, the low-vision rows in Living rooms, bedrooms and stairs apply, and their eye doctor settles what they need. Ask the authority
2. The bulb trial
A bulb trial is buying one of each candidate bulb, using it in place for about a week at the hours the room is used, and deciding by a written date to keep or return it. It is the cheapest test in this manual, and it turns a provisional row into a confirmed or a rejected one.
Trial rather than buy a full set, because the label compares bulbs but does not predict how one looks in your room. Under the FTC's labeling rule (16 CFR 305.23), the Lighting Facts label reports brightness in lumens, a yearly cost at 3 hours a day and 11 cents per kWh, life in years at 3 hours a day, light appearance in kelvin and energy used in watts. It reports no color rendering, no flicker and no dimmer compatibility. Product-specific The bulb label reader walks through each line.
Setting up a fair trial
- Choose from the plan, not the shelf. Take the row's lumens, kelvin and CRI to the store, and look for "dimmable" if the bulb goes on a dimmer. If the fixture is enclosed, read the package for the enclosed-fixture line. Compare the label's Energy Used watts with the fixture's maximum-wattage label: NFPA's consumer guidance says to match the fixture's recommended wattage and to read LED labels to be sure the bulb suits the fixture and location.
- Write the return-by date the day you buy. Stores set return terms; we do not know yours. Keep the receipt and the box until the date passes.
- Change one thing at a time. If you change the bulb and move the lamp on the same evening, a better reading cannot say which change did it. Try the bulb first, note it, then move the lamp. Test it
- Use it when the room is used. A living room bulb is judged in the evening, a bathroom bulb in the morning at the mirror.
- Repeat the checks from Survey and test your rooms with it. The book-block glare test from the usual seat, the shadow check, the color check with a white sheet, a skin tone and a red object, and the slow-motion video for a bulb on a dimmer (glare tests, flicker test).
A trial between two bulbs reads best when they differ in one figure. Two 800-lumen CRI 90 bulbs at 2700 K and 3000 K compare color temperature and nothing else. Test it Preference is a legitimate result: Bulbs, labels and color showed that package names for color temperature are marketing conventions, and no source we read says one kelvin figure is right for a living room. If the household prefers 2700 K in the evening, write that down as the reason. Preference
Change a bulb with the light off and the bulb cool. If a fixture has no wattage label, the Consumer Product Safety Commission's checklist says to use a bulb of 60 watts or less, and 25 watts for fixtures that take miniature bulbs. If the trial turns up a warm or discolored switch plate, buzzing, a burning smell, or lights that flicker or dim when an appliance starts, stop using that light and call a licensed electrician; NFPA and the Electrical Safety Foundation both list these signs. That is not a bulb result.
3. The retest, read honestly
A retest repeats the first test after a change: the same device, the same spots, the same time of day, the same lights on, and three readings averaged at each spot. Its value comes from what stays the same.
The reason is the device. In a 2022 University of Maribor study (DAAAM International Scientific Book), ten phones were compared with a reference lux meter under one LED light. At 400 lux the closest phone was about 1 percent off and the worst about 99 percent. Each phone's error was fairly steady across light levels under that one light, which is why the same phone in the same spot can show a change; the error shifted under daylight and mixed light. Product-specific Odenwald (2020) calibrated phones against a meter and still found errors of about 16 percent from 100 to 5,000 lux and about 18 percent below 100 lux, where evening home readings sit. Survey and test your rooms covers phones as meters in full.
Two rules follow:
- Report a ratio, not a light level. "The phone read about twice as much at the sofa arm" is a statement the phone can support. "The sofa arm now gets 81 lux" is not.
- A change smaller than the phone's error is not a change. With errors near 18 percent left after calibration at home light levels, a reading that moves 5 or 10 percent says nothing either way. Write "about the same." This manual uses about 20 percent as its line, rounded up from the calibrated figure; an uncalibrated phone is likely worse, so a change just past the line is still weak evidence. Convention
Watch one more source of drift. When the change was a bulb color, the light the phone sees changed too, and the Maribor study found the error moved when the light source moved. A modest gain after a color swap is weaker evidence than the same gain after moving a lamp. Test it
The retest also repeats the tests that need no meter: glare, shadow, color and the slow-motion video. A plan aimed at glare succeeds when the book-block test no longer finds a bright source in view from the seat, whatever the phone says.
Reading the before and after
Write each after row in the tests sheet marked "after", with the date and time, and compare spot by spot:
| After compared with before (same device, same spot) | Write | What it supports |
|---|---|---|
| Up by about half again or more | The ratio: "about twice as much" | A difference at this spot that the phone's error is unlikely to explain. |
| Up by about a fifth to a half | "a little more" | Probably more light; weaker evidence, especially after a color swap. |
| Within about a fifth either way | "about the same" | No change the device can show. Look at the other tests. |
| Down by more than about a fifth | "less" | First check that the same lights were on and nothing was in the way. |
The bands are this manual's reading of the two phone studies, not a published standard. Convention They are wide on purpose.
A retest that shows improvement on your phone is evidence for that room and that spot, not proof of a light level, and not proof that a published target is met. A plan that needs wiring is finished only after the electrician's visit and the post-installation check. This manual makes no claim that any plan saves energy or money, improves sleep, prevents falls or protects eyesight. A change in vision goes to an eye doctor; a fall, a change in balance or a sleep problem goes to a physician.
4. Put the work in order
Do the plan's rows in this order, so each stage's retest informs the next:
- Bulbs and lamps first. They are yours to change in any home and reversible within a return window. A brighter bulb or a lamp moved closer can change what the room needs: halving a small source's distance gives about four times the light on the page (How light works in a room). Physical principle
- Plug-in and battery fixtures next. Plug-in sconces, picture lights, under-cabinet strips and automatic nightlights add layers without wiring. Renters ask the landlord in writing before fixing anything to a wall or cabinet, even with adhesive. Cords stay out from under rugs and out of doorways, as NFPA's guidance says.
- Electrician work in one visit. Everything behind a wall plate or a fixture canopy goes on one brief: new or moved fixtures, switches, dimmers, smart switches, a switch at the top of a stair. The electrician sees the whole job, and you compare quotes against one document (Working with an electrician, the brief). Ask the authority
The first two stages often change the third. A plug-in under-cabinet light changes the counter's task layer, and how much general light the ceiling still has to supply becomes a question for the electrician's layout. A pair of nightlights can cover the night path while the stair-top switch waits. Write the effect of each stage into the next stage's rows before the brief goes out. After the electrician's work, run the after-the-work checklist and the retest (Working with an electrician, after the work).
The evening and the night, as a household agreement
Two rows depend on people more than on fixtures: which lights stay on in the last hours before bed (Switches, dimmers and evening light) and which are on at night along the path to the bathroom (Living rooms, bedrooms and stairs). Write each as a household agreement: a few lines everyone who lives there has read, naming the lights, the times and who turns them on and off. A night path only works if the nightlights stay plugged in.
The CIE's 2024 position statement on integrative lighting describes the pattern the evening rows follow: bright days, low light in the evening and darkness at night. It also calls labelling a light "healthy" or "unhealthy" by its color temperature unhelpful and potentially misleading, so the agreement names lights and times, not a kelvin figure that claims an effect. Convention The agreement is not a sleep treatment or a fall-prevention measure (evening light, the night path).
5. The binder, and when to look again
The lighting binder is every sheet in this manual saved together as one file from the binder page. The sheets live in this browser only; the export file is the copy that leaves the device, so it is the copy to keep. Export after each evening of testing, and print the binder before an electrician's walkthrough or a talk with a landlord. Beyond the sheets, it holds:
- Bulbs by fixture. The fixtures sheet, updated after each trial, so a failed bulb has a row that says what to buy.
- Compatibility lists for every dimmer in the home. A replacement bulb for a dimmed fixture comes from the list.
- The brief, the quotes and the electrician's paperwork: invoice, fixture sheets, permit and inspection records. Note where the paper originals are.
- Trial results, returns included. A rejected bulb does not need trying again.
- A recall check once a year. The Consumer Product Safety Commission's recall search has categories for light bulbs and for floor and table lamps. Search the makers in the fixtures sheet and write the date on the safety sheet.
When to look again
- Someone new lives in the home. A baby, an older parent, a roommate who works nights: each brings rows.
- Someone's eyesight changes. Their eye doctor first, then the plan.
- A bulb fails early. The label's life is a projection at 3 hours a day, and heat in an enclosed fixture shortens LED life. Check whether the bulb is marked for enclosed fixtures (LED life and heat).
- A dimmer starts to buzz or a light starts to flicker. A new bulb on an old dimmer is the first suspect, and the compatibility list is the check (Switches, dimmers and evening light). Flickering lights are on NFPA's list of reasons to call a licensed electrician, and a buzzing, hot or discolored plate is on ESFI's. If a bulb swap does not settle it, or a plate is hot, stop using it and call. Ask the authority
- The room changes. New paint, a moved desk, furniture in front of a lamp. Reflectance and distance are still at work; retest.
A yearly check
Once a year, on a date written in the binder: run the recall search, walk the safety checklist for each room, run each dimmer through its range with the slow-motion video at the lowest setting you use, and take one set of evening readings in the first room with the same device. A reading that drifts down with nothing changed in the room is one sign that LED output has fallen, which is what the life rating measures. The interval is our suggestion; no source we read sets one for a home. Preference
6. See it See it
Marisol's living room, tried and retested. Marisol Ortega rents a one-bedroom apartment; her living room is 12 by 14 ft with medium gray walls. All readings, dates and prices here are invented for the example.
Known. Before (2026-10-06, about 8:30 p.m., phone app, average of three each): sofa arm 38 lux, coffee table 52, desk 61. The ceiling fixture is an enclosed glass dish labelled 60 W maximum, with two 800-lumen bulbs, one 2700 K and one 5000 K. The floor lamp behind the sofa had a 450-lumen 2700 K bulb. Her problems: too dark in the evening, and colors that don't match.
The trial. On 2026-10-10 she bought two 800-lumen CRI 90 bulbs at $6 each, return-by date 2026-11-09: a 2700 K bulb for the ceiling in place of the 5000 K, and a 3000 K bulb to compare in the floor lamp. After a week the 2700 K bulb matched the other ceiling bulb and the gray wall no longer looked blue on one side: keep. The 3000 K bulb was fine for reading, but she prefers 2700 K in the evening: return. She then put an 800-lumen 2700 K bulb in the floor lamp in place of the 450 and moved the lamp beside the sofa arm.
The retest (2026-10-13, about 8:30 p.m., same phone, same spots): sofa arm 81, coffee table 70, desk 64. She writes it as the phone can support it: the phone read about twice as much at the sofa arm, a little more at the table, and about the same at the desk. The desk moved 5 percent, inside the phone's error, and the table's gain came after a color swap, so it is the weaker of the two.
Assumed. That her phone's error stayed steady between the two evenings. It is her assumption, and the reason she reports ratios.
Open. The desk still has a heavy shadow from her own body with the ceiling light behind her; a desk lamp on the side opposite her writing hand is the next row, and the next retest settles it. Whether her readings are accurate stays unresolved by design. The glare from the ceiling dish stays an open row. The landlord answered in writing that adhesive plug-in under-cabinet lights in the kitchen are allowed if removed without damage, so that row moves to "next". Nothing in her plan is electrician work.
Her ceiling and lamp now total 2,400 lumens. Under this manual's assumed surface band, the calculator gave 1,460 to 1,950 lumens on the Defense Department line and 5,250 to 14,000 on the commonly cited line. She is above the first and well below the second, and neither settles it; her readings and her comfort on the sofa do.
- Comparison between Lux Meter Apps and Illumination Measuring Devices (DAAAM International Scientific Book 2022, PDF): ten phones against a reference meter; the 400-lux figure shows how far apart phones read under one light.
- Smartphone Sensors for Citizen Science Applications: Light and Sound (Odenwald, 2020): the error left after calibration, by light range.
- Recalls and Product Safety Warnings (U.S. Consumer Product Safety Commission): the search for the yearly recall check.
- Educational Messages Desk Reference, 2026 edition (NFPA, PDF): chapter 12 lists the warning signs that end a trial and start a call to a licensed electrician.
7. Practice Practice
Minimum: one bulb tried in the first room for a week, one retest of the spots from Survey and test your rooms, and the binder exported. Time: about an hour of work over a week, plus the evenings of living with the trial. Materials: the bulb your plan names and its receipt, the same phone or meter you used in Survey and test your rooms, a book, a white sheet of paper and a red object.
- Read the plan against your problems. In the layers sheet, give every setup problem a row and every row a lamp or fixture, a kelvin figure, a control and a status.
- Buy one trial bulb. Check it against the row and the fixture's labels as the trial section describes, and fill in the trial sheet, return-by date included.
- Live with it for a week. Run the glare, shadow and color checks once with it, and the slow-motion video if it is on a dimmer.
- Retest the same spots. Same device, spots, hour and lights, three readings each. Mark the rows "after" in the tests sheet and write each comparison as a ratio or "about the same".
- Decide, record and export. Keep or return with a one-line reason; update the plan row's status and the fixtures sheet; save the file from the binder page.
Repeat the trial and retest for each chosen room in the plan's priority order. Write the household agreement for evening and night. If the plan has electrician rows, send the brief once the first two stages are retested, and run the after-the-work checklist when the work is done. Put a date for the yearly check in the binder.
8. Your rooms Your rooms
9. Check your work Check your work
Criteria
- Does every chosen room have a row for each layer it needs, and does every setup problem point to a row?
- Does the trial sheet have a return-by date and a keep-or-return decision with a reason?
- Were the before and after readings taken with the same device, spots, hour and lights?
- Is each comparison a ratio or "about the same", with no claim of a light level?
- Is the electrician work, if any, on one brief?
- Is the binder file saved where you will find it next year?
Worked example
Marisol's living room (fictional example) meets the criteria, with one gap. Both problems have rows: matching 2700 K bulbs for the color mismatch, and a brighter lamp moved closer for the dark sofa. Her trial sheet has dates, prices, a return-by date and reasons. Her retest used the same phone, spots and hour, and she reported ratios. Her desk row is honest: about the same, shadow unchanged, a desk lamp next. The gap: she changed the floor lamp's bulb and its position before the retest, so the retest does not show how much of the sofa arm's doubling came from each. She notes it, and the row stays provisional until the desk-lamp retest gives her a second evening to compare.
Common mistakes
- Retesting with a different phone, in daylight, or with an extra lamp on.
- Writing the after reading as a light level that "meets the target", or reading a 5 percent change as an improvement.
- Missing the return-by date, so the trial becomes a purchase by default.
- Keeping the binder only in the browser. Clearing site data loses it; the exported file does not.
What is still unresolved
This manual cannot tell you that your rooms now have enough light, or the right light; your before-and-after readings and the people who use the rooms say whether the change helped. Work behind a wall plate is settled by the electrician's visit and the after-the-work check, permits by your building department, changes in eyesight by an eye doctor, and sleep problems, falls and light sensitivity by a physician.
10. Knowledge check and scenario
Why does the retest have to use the same phone in the same spots?
A desk reading goes from 61 to 64 lux on the same phone. What do you write?
Why do bulbs and lamps come before the electrician's work?
What does the Lighting Facts label leave out that a trial checks?
(Go deeper) What does a yearly reading that drifts down, with nothing changed in the room, suggest?
Checklist
Have you just done what this manual teaches? If it is still fresh, we would like to hear about it. We are looking for volunteer guides to add a few short passages from their own experience to this manual. Write to guides@learnthings.online for the details.