When I walk into a client's home at night, I look up before I look anywhere else. Most homes are lit the same way at 9pm as at 9am: every ceiling light on, the same bright white, from breakfast to bedtime. Circadian lighting at home means the opposite. Your light follows the sun. Bright and high during the day, low and warm in the evening, dark at night. It is one of the simplest changes I recommend, and one of the most overlooked, in homes and workplaces alike.
Your Eyes Tell Time
Your eyes do more than see. The retina holds a small set of cells called intrinsically photosensitive retinal ganglion cells, or ipRGCs. They do not help you read or recognize faces. Their job is to report light to the body's master clock, a cluster of cells in the hypothalamus that keeps your daily rhythms on schedule (Webvision, University of Pittsburgh).
That clock was built for the sun. For most of human history, light meant day and darkness meant night. A lamp at 11pm sends the same signal a sunrise does, and your body has no way to know the difference.
In 2022, a group of sleep and circadian researchers published a consensus on how much light people need, and when (Brown et al., PLOS Biology, 2022). The direction is clear:
- Bright during the day.
- Dim for about three hours before bed.
- Dark during sleep.
The paper measures light in a specialized unit tied to these cells, not in the numbers printed on a bulb box. So I do not give clients a number. I give them a direction, and a home that makes it easy to follow.
The Four Parts of the Day
Morning: let the day in
Open the shades as soon as you are up. Eat breakfast by the brightest window you have. If you wake before the sun, or your bedroom faces a wall, a sunrise alarm brightens the room slowly before your alarm time, so your first signal of the day is light rather than sound.
Workday: bright where you work
Most people spend their day under light that is too dim for the clock and too harsh for the eyes. The answer is bright task light where you actually work: the desk, the kitchen counter, the table where you read. Place your desk near a window if the room allows. This applies to a home office, a studio, a clinic or a corporate floor. Wherever you spend your working hours, your clock reads that light as day.
Evening: low, warm and below eye level
About three hours before bed, turn off the overhead lights. Switch to lamps that sit low in the room, on side tables and floors, with warm shades. Light that comes from above reads like midday sun. Light that comes from low in the room reads like firelight at dusk. Screens count too, so dim them and keep them at arm's length.
Sleep: dark
Blackout curtains or shades. No standby glow from chargers, televisions or clocks. If you need a light to find the bathroom at night, keep it low to the floor and dim.
The trend I talk clients out of: "daylight" bulbs in every fixture. They are sold as energizing, and during the day they have a place. Left on all evening, they keep telling your body it is noon long after the sun has set. Daylight belongs to the day.
What I Recommend
You do not need to rewire a house to light it like the sun. I think about this in four tiers, from a single lamp to the architecture itself.
Start with the bedside
- Lumie Bodyclock: a sunrise alarm that brightens gradually before you wake. The easiest first step, and it works in any bedroom, owned or rented.
Upgrade the desk and reading chair
- Dyson Solarcycle Morph desk lamp: a task lamp built to follow daylight, so one lamp can give you bright light for work and a warmer, softer light in the evening. There is also a floor version for a reading corner or living room.
Light the whole home
- Lutron Ketra: whole-home tunable lighting that shifts through the day on its own. Designed and quoted through a dealer, and best planned during a renovation or new build.
- Savant Daylight Mode: the same idea inside a full smart home system, for clients who want lighting, shades and climate on one schedule. Also dealer-quoted.
Bring in the real thing
- VELUX skylights: the most direct way to bring daylight into a dark room, a stairwell or a top-floor office.
- Solatube: tubular daylight devices that reach halls, closets and interior bathrooms where a full skylight will not fit.
Members can see Maggie Li's picks for your lighting in the store.
The Classical Feng Shui View: Yang by Day, Yin by Night
In Classical Feng Shui, every space moves between yin and yang. Yang is bright, active and outward. Yin is dim, still and restful. A healthy home does not stay in one state. It moves with the day, the way the sun does.
A home lit at full brightness from morning to midnight is stuck in yang. The qi never settles, and neither do the people living there. A home that stays dim all day is stuck in yin, heavy and slow. When I read a home, I look at where each room sits on that scale, and whether it can shift.
The science and the classical principle describe the same pattern from two directions. The researchers call it a circadian rhythm. The classical texts call it the movement of yin and yang. Either way, the instruction is the same: let your light rise and fall with the sun.
Some rooms should lean one way by design. A bedroom is a yin room and should be the calmest, darkest space in the home. A kitchen, a home office or a workplace is a yang room and should be bright while it is in use. Clients report that when each room is lit for its purpose, the whole home feels easier to live in.
Start Here
Tonight, three hours before bed, turn off every overhead light in the rooms you use. Light only the lamps that sit low, with warm shades. Do the same for a week and notice how your evenings feel.
The Energizing Home series. Start with the hub · Previous: CO2, Air Quality and Fatigue · Next: The Water You Shower In
Want Maggie Li to read your home? Start here.
Maggie Li is the founder of The REN Method, a Classical Feng Shui and BaZi practice. She trained under Dr. Simona F. Mainini and is certified by the American Council of Feng Shui Masters.