Indoor lighting

LGT

250 / 10 / 1target light at the eye (mEDI): day / evening / night

Your eyes read brightness; your body's clock reads the blue-cyan signal these numbers track. By that measure most homes run too dim in daylight and too bright after dark.

A comfort parameter, not a contaminant

Stasis Home ResearchEvery claim on this page is graded against peer-reviewed health research and linked to its primary source.Updated 2026-06

Light is the body's master timing signal, not a pollutant. A specialized set of cells in your eye reads it and sets the clock that runs your sleep, energy, and mood. Modern homes break that signal two ways: too little circadian light by day, too much by evening and night. The fix is structural. The right bulbs in the right rooms at the right times, plus a dark bedroom, so you sleep deeper, wake up sharper, and stop being tired.

What it is, and where it comes from

Light is information before it is brightness. A small set of cells in your retina (intrinsically photosensitive retinal ganglion cells) carries a pigment tuned to blue-cyan light and reports straight to the master clock in your brain, the suprachiasmatic nucleus. That clock then schedules melatonin at night, the cortisol burst on waking, body temperature, and the daytime alertness drive. The metric that tracks this signal is mEDI, melanopic equivalent daylight illuminance, which weights light by what the clock actually responds to rather than by what looks bright to your eyes. The two do not move together: a warm 500-lux lamp can read low mEDI, and a cooler 300-lux daylight bulb can read high. Indoor lighting is a parameter, the same kind of body-comfort setting as humidity or CO2, not a contaminant that arrives and leaves. The mismatch is a modern invention. The body evolved on a bright-day, dark-night contrast of roughly a hundred thousand lux outdoors at noon down to near-dark at night. Cheap, cool LED and bright screens collapsed that contrast: most post-2015 homes run moderate cool light across every hour, which is exactly the wrong signal for a clock built on contrast.

Why it matters

Light does not poison you. Run on the wrong schedule, it quietly flattens the timing system that everything else depends on. Two failures stack. By day, a living room reads bright to your eyes but often falls short of the circadian signal because the blue wavelengths the clock needs get filtered out by windows and warm bulbs, so the daytime alertness drive never gets sharpened. By evening and through sleep, ordinary household light lands at the eye right on the steep part of the response curve, where the difference between a dim warm lamp and a bright overhead is the difference between melatonin rising on schedule and melatonin staying suppressed. Bright light in the three hours before bed can compress a night's sleep by close to an hour, which adds up to most of a lost night each week. And the bar for harm overnight is lower than people expect: the amount of streetlight that leaks around curtains, the glance-and-it-looks-mostly-dark bedroom, is enough that a single night of it measurably worsens next-morning blood sugar handling and raises heart rate during sleep. None of this is catastrophe. It is a steady tax on your sleep, energy, and focus, and it is one of the few you can design out of the house rather than live with.

A multidisciplinary expert consensus set the indoor light targets the body's clock needs: about 250 mEDI at the eye through the day, 10 or below in the three hours before sleep, and 1 or below during sleep. These are the numbers Stasis designs a home's lighting to hit.Brown et al., 2022 (PLOS Biology; recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults)
A single night of about 100 lux during sleep, roughly the streetlight that leaks past ordinary curtains, raised heart rate and lowered heart rate variability overnight and left next-morning insulin handling measurably worse than a near-dark room. One night. This is why a dark bedroom is infrastructure, not luxury.Mason et al., 2022 (Proc Natl Acad Sci USA; light exposure during sleep impairs cardiometabolic function)
Ordinary room light before bed, compared with a dim sub-3-lux room, suppressed melatonin by about 71 percent and cut short the window the hormone is active, which is the mechanism behind delayed and compressed sleep on bright evenings.Gooley et al., 2011 (J Clin Endocrinol Metab; exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans)
Sensitivity to evening light varies about fiftyfold between healthy adults: some people suppress melatonin meaningfully at dim levels while others tolerate far more, and the same household can hold both, which is why the answer is dimmable warm light rather than one fixed setting.Phillips et al., 2019 (Proc Natl Acad Sci USA; high sensitivity and interindividual variability in the response of the human circadian system to evening light)

What we grade it against

Where the health research draws the line, versus the legal limit.
Contaminant	Health-based level	Source (health-based)
Daytime light at the eye (mEDI)	at least 250sustained roughly 4 hours, vertical plane at the eye; strengthens circadian entrainment and daytime alertness	Brown et al., 2022 (PLOS Biology) consensus recommendation
Evening light at the eye (mEDI)	10 or belowthe 3 hours before sleep; keeps melatonin onset on schedule. Warm 2700-3000K, avoid bright overhead	Brown et al., 2022 (PLOS Biology) consensus recommendation
Nighttime light at the eye (mEDI)	1 or belowduring sleep; effectively complete darkness. Blackout shades, with a sleep mask as backup	Brown et al., 2022 (PLOS Biology) consensus recommendation
Color rendering (CRI)	90 or abovefor kitchen, bath, home office, bedroom mirror; 80 is the residential floor. Below this, color reads wrong and quality is usually cut elsewhere too	IES Lighting Library (TM-30 color rendition); WELL Building Standard v2 Light
Flicker (modulation depth below 100 Hz)	under 8%the no-observable-effect bound; cheap LED drivers often exceed it and cause eye strain and headaches	IEEE 1789-2015 recommended practice (flicker)

Health-based levels come from peer-reviewed research and government risk scientists working without cost constraints. Legal limits are enforceable compromises. Your report grades to the health column.

What helps

Direct fixes

Tunable-white smart bulbs in the bedroom, living area, and home office
Bulbs that shift from cool daylight in the morning to warm dim at night, on a schedule, deliver the day-bright and evening-warm contrast the clock needs without anyone managing it by hand. Stasis specs them at CRI 90 or above and flicker-compliant so color reads true and there is no eye strain, and prefers the Matter standard so they are not locked to one app or ecosystem. This is the wedge: the right bulbs in the right rooms at the right times.
A bulb shifts the light you are already in. It cannot help during the hours you are away from it, and morning outdoor sun is still the strongest signal available and free for anyone who can take it. The bulb is the workaround for the body's clock, not a substitute for daylight or for a dark bedroom.
Bedroom blackout: blackout curtains or shades, sleep mask as backup
Pulls the bedroom toward true darkness during sleep, where the body needs essentially no light. This is a foundational Tier 1 essential, not an upgrade, because the cardiometabolic evidence kicks in at the low light levels that leak into almost every suburban bedroom. The honest customer rule: if your bedroom is not dark enough to be inconvenient when you wake at night, it is not dark enough.
Blackout controls light, nothing else. It does not address heat, noise, CO2, or humidity in the room, which carry their own fixes. And it only works if the small sources go too: cover charger LEDs, alarm-clock displays, and standby lights, or they undercut the curtains.

Bigger retrofits

Whole-home circadian system: tunable bulbs across rooms, smart switches and shades, concierge install
For households that want the day-to-night light schedule running hands-off across the whole home, not one room at a time. Tunable bulbs in the primary rooms, smart switches where fixtures take dumb bulbs, and automated shades to reveal daylight, designed and tuned by Stasis on the same subscription and service cadence as the rest of the audit.
Switch and shade integration needs a professional install, so this is a concierge retrofit, not a DIY product. It still cannot manufacture daytime daylight in a deeply interior, north-facing room. Where the architecture starves a room of light, supplemental morning bright light is the answer, not more evening output.

Free and behavioral

Phone and laptop on warm night mode in the evening; skip the wellness gadgets
The built-in warm modes (Night Shift, Night Light, f.lux) cut a screen's evening blue load for free, which is the part that matters near bedtime. This rides the app's evening reminder rather than a purchase.
These help but do not cancel a bright screen held close to the eyes; dimming and distance still matter. And the add-on market overreaches: daytime blue-light glasses show no benefit beyond placebo for healthy adults per the American Academy of Ophthalmology, and salt lamps and negative-ion lamps have no evidence base. Stasis does not recommend them.
Morning bright-light box (seasonal and shift-work cases)
A 10,000-lux therapy box delivers a strong morning circadian signal on days a person cannot get outdoor sun, which matters most for documented seasonal mood symptoms and shift workers. These boxes emit visible white spectrum without UV.
In a sun-rich market this is a specialty Tier 3 item because outdoor daylight is abundant; it becomes a front-line default only in far-northern winters. It is not a tanning bed or sun lamp: those carry real UV skin-cancer risk and deliver no circadian benefit a therapy box does not.

Light is the one environmental input the modern home gets backward by default, and it is also the most fixable. Your circadian system is the master clock for your sleep, your energy, your mood, and how sharp you feel through the day, and it runs on a bright-day, dark-night contrast that cool LED and bright screens have flattened. The bulb market makes it worse: it competes on price and brightness, which sit on the box, while color quality and flicker, which you cannot see at purchase, get cut. Stasis curates the right bulbs in the right rooms on the right schedule, plus a genuinely dark bedroom, so the home matches the signal your body needs instead of fighting it. Same Stasis app, same subscription, same service cadence as your air, your water, and your humidity. You sleep deeper, wake up sharper, and stop being tired.

Common questions

What are the right indoor light levels for sleep and energy?

Expert consensus sets three targets measured at the eye in mEDI, the unit that tracks the body's clock: about 250 through the day (bright, cool light), 10 or below in the three hours before bed (warm and dim), and 1 or below during sleep (a dark bedroom). Most homes run too dim by day and too bright at night.

Why do I wake up tired even after a full night in bed?

Often the light, not the hours. Bright light in the evening pushes your sleep hormone late and compresses the night, and even faint light leaking into the bedroom during sleep fragments it and shifts your body toward an aroused state. Meanwhile dim indoor days leave your daytime alertness signal weak. Restoring the day-bright, night-dark contrast is what makes mornings easier.

Does light in the bedroom at night really matter if it is dim?

Yes, more than people expect. In a controlled study, one night at about 100 lux, the level of streetlight that gets past ordinary curtains, raised overnight heart rate and worsened next-morning blood-sugar handling versus a near-dark room. The working rule: if you can make out the room when you wake at night, it is letting in too much light.

Do blue-light glasses help?

Not for general daytime use in healthy adults. The American Academy of Ophthalmology finds no evidence they reduce eye strain or protect the eyes beyond placebo. What does help near bedtime is cutting evening light load, which the free built-in warm modes on your phone and laptop already do. Stasis does not recommend daytime blue-light glasses, salt lamps, or negative-ion lamps.

Are expensive bulbs worth it, or is brightness all that counts?

Brightness and color temperature are what sit on the box; color rendering and flicker are what you cannot see at purchase, and that is where cheap bulbs cut. Many sub-$5 LEDs render color poorly and flicker enough to cause eye strain and headaches. Stasis specs bulbs at CRI 90 or above and flicker-compliant so color reads true and your eyes are not working against a strobing light all day.