Frequently Asked Questions
Our most commonly asked questions about living with Sunday Light.
Indoor sunlight and how it works
What is Sunday Light?
Sunday Light is often described as the closest thing to sunlight you can buy. It hangs from the ceiling like a chandelier, and looks and feels like having the sun and sky indoors.
What makes it unique is that it delivers real, physiologically-meaningful daylight, not just the look of it. It's bright enough to have physiological impact: 34,500 lumen output, which is the equivalent of being outside. Its high quality, full-visible-spectrum light shifts through the day to follow the sun, from blue-rich, bright light in the morning and warm, dimmer light in the evening, as if you were outdoors.
It is engineered to do all of this passively, as part of your everyday routine, so bright daylight improves your mood, sleep and energy without you having to think about it.
Find out more about why we built indoor sunlight.
How does Sunday Light work?
Sunday Light consists of a high quality LED, which shines up onto a large diffusing panel that scatters the light across the sheet, the same way the atmosphere scatters sunlight. That's what makes it feel like daylight at a comfortable brightness that you can sit under all day, rather than a point source. A sealed water-cooling system is what lets it run that bright all day, which a normal air-cooled light can't. The colour temperature shifts on a schedule, blue-rich at 6000K in the morning down to a warm 2650K in the evening.
Find out more about how Sunday Light works.
Why is Sunday Light different to a normal ceiling light?
Most ceiling lights are made for visual comfort and decoration, not biological impact. They put out relatively low light and rely on air cooling, which limits how bright they can run continuously.
Sunday is engineered from the ground up to deliver daylight-level brightness across a whole space. At those levels brightness alone isn't enough, the light also has to stay comfortable over long periods, so we use a combination of high-fidelity LEDs, atmospheric light dispersion across the panel, and a sealed water-cooling system.
The result is daylight you can live under all day, which is what supports mood, focus and sleep. Read more about how Sunday Light works.
How is it different to an artificial skylight?
An artificial skylight recreates the look of a fixed sky.
Sunday not only recreates this look, but also the physiological impact of bright light for your body. It has been engineered to deliver daylight-equivalent brightness (34,500 lumen output) to support circadian health. It also shifts colour temperature through the day to follow the sun and offers automated scheduling and jet lag management via the Sunday Light App.
Health, sleep and circadian benefits
Why is bright light good for health?
Bright light is one of the most powerful signals your body uses to regulate sleep, mood and alertness. Regular bright light, especially first thing in the morning, helps align your body clock and regulate your sleep-wake patterns. Most indoor lighting is too dim to send that signal.
Read our guide on how to use bright light to improve your life.
How can bright light help Seasonal Affective Disorder (SAD)?
Seasonal Affective Disorder (SAD) is commonly associated with reduced daylight exposure during darker months. Research has consistently shown that bright light exposure at approximately 10,000 lux, improves mood and energy in people affected by SAD.
Sunday delivers that brightness naturally across a room, so it's easy to get as part of your routine.
Learn more about bright light therapy and circadian health →
How is Sunday Light different to a smaller SAD lamp?
In short, SAD lamps focus light on a person. Sunday Light builds daylight into the indoor environment.
Most SAD lamps deliver high light intensity only at very close range, which typically requires sitting inches from a small device for a fixed period each day. This makes it hard to keep up with as part of your routine.
Sunday Light takes a different approach. It delivers daylight-level brightness across a room, allowing physiologically meaningful light to be experienced naturally as part of everyday life, while you work, eat, or move through a space. There’s no need to sit still or face a lamp.
How can bright light help my sleep?
Bright light during the day, especially the morning, signals to your body that it's daytime, which reinforces natural sleep timing at night.
Most indoor lighting is not bright enough to provide this strong signal, which results in inconsistent and lighter sleep. Regular exposure to bright light supports stronger day-night contrast, helping many people fall asleep more easily and wake feeling more rested.
Can it help with jet lag?
Yes. Sunday Light has jet lag features as part of the Sunday Light app. Simply enter your flight timings and it schedules the light to shift your body clock to prepare for your travels.
The app uses your travel dates and destination to time brighter and warmer light at the right hours, nudging your rhythm towards the new time zone faster than it would shift on its own.
Read more: Living in sync with daylight
What is the science and research supporting it?
Sunday Light was built on decades of circadian and bright light research. Our founder, Nat Martin, studied circadian science as part of his undergraduate degree at Oxford University, and this is where he first met Professor Russell Foster, Head of the Circadian and Neuroscience Institute at Oxford and advisor to Sunday Light, who discovered the light receptors in the eye that set your body clock.
Brightness, colour and comfort
How bright is Sunday Light?
Sunday emits up to 34,500 lumens of daylight-level brightness, reaching around 10,000 lux at 60cm.
For context, a well-lit office is only about 500 lux, far below the level your body clock really responds to.
It stays comfortable to sit under because the light spreads across a large panel and is scattered across a room rather than firing from one point. It is also fully dimmable and can be set on a schedule to wind down towards the end of the day.
Could it be too bright or uncomfortable for me?
Sunday is designed to stay comfortable even at high brightness, because it scatters light across the whole room rather than pointing down directly at you.
People vary in how sensitive they are to light, so it's fully dimmable and shifts from cool 6000K daylight to warm 2650K evening light, set it to whatever feels right.
Most people set an automated schedule once and let it run, the right light at the right time.
Can you change the colour temperature?
Yes. Sunday Light features adjustable colour temperature, ranging from warm evening light (2650K) to cooler daytime light (6000K). You can use the remote with presets for 3 times of the day, or use the app to schedule this to follow the sun.
This means you can always get the right light at the right time of the day: brighter and cooler when you want energy and focus in the morning, and warmer and softer as the day winds down.
Is the colour quality good?
Yes, Sunday Light's colour quality is very high and almost exactly equivalent to sunlight as measured by the Colour Rendering Index (CRI) of 97+.
This means that colours look true to life, the way they do in daylight. This makes the light feel natural rather than flat, like typical lower quality LED lights used indoors.
How loud is the Sunday Light?
Effectively inaudible in typical rooms. Maximum output is 25 dB(A) at one metre, significantly quieter than a fridge.
Your space
Is there a minimum recommended ceiling height for the Sunday Light?
The typical minimum is 2.4m (94 inches). Higher is fine, the wires hanging the light adjust. If your ceiling is lower, email enquiries@sundaylight.cc in advance and we'll advise on suitability.
What is the ideal room size for Sunday Light?
It works well in both small and large spaces, but we usually recommend anchoring it over something like a dining table, kitchen island, coffee table or desk.
The key thing is to put it where you naturally spend time during the day, particularly the mornings, so you get the most from the light.
I'm not sure if it will fit in my space.
Send us a photo or a plan, or come and see one in person, and we'll tell you honestly whether it'll work before you order.
Can it be controlled by my smart home platform?
Yes. Sunday connects to smart home and building systems including DALI, Casambi and Home Assistant.
That said, we usually recommend using our own Sunday Light app, which is purpose-built for circadian use with bespoke schedules, presets and the jet lag feature, rather than a general lighting controller.
If you have a specific platform in mind, email us at enquiries@sundaylight.cc and we'll confirm the best way to set it up for your home or building.
Using Sunday day to day
Do I have to sit in front of it?
No, Sunday Light has been built to be passively part of your environment. You live in the room and the daylight-level brightness reaches you.
No need for sessions, sitting still or facing a panel like you would with an SAD lamp.
How do I control it?
You can use either the physical remote which comes with it, or the Sunday Light App.
The app is where the scheduling, presets and jet lag features live.
Can the Sunday Light be scheduled to turn on at certain times?
Yes. You can schedule it to turn on and off at set times, brightness levels and colour temperatures, so the light follows the natural rhythm of the day, bright and energising when you need it, softer and warmer as it winds down, without manual adjustment.
Use the Sunday Light App to set your schedules, create custom presets and access the jet lag assistant to help you prepare for travel.
Where should I put Sunday Light in my home?
Where you naturally spend time during the day, particularly the mornings, commonly above a dining table, kitchen island, desk or shared living space.
Because it lights a whole space, it doesn't need to be directly above you. For guidance on your space, email: enquiries@sundaylight.cc.
What does the app do?
The Sunday Light App allows you to schedule the light to follow the sun according to your routine. Set it once, and then get the right light at the right time of the day, every day.
The app also has extended presets, brightness and colour control, as well as jet lag management features to help you when preparing for travel.
How much does it cost to run the Sunday Light?
At full brightness it uses about 400W, roughly £0.09 per hour at typical UK electricity rates (about $0.07 in the US), and less when it's dimmer.
Ordering and shipping
How do I order a Sunday Light?
Order through the Sunday Light product page.
If you have any questions before ordering, or you are looking to place a bulk order, please email enquiries@sundaylight.cc. Our team will guide you through the process and answer any questions.
How much does delivery cost and how long does it take?
Your light ships within 5 working days of ordering, and delivery is via DHL Express. Shipping is free worldwide, and all duties and taxes are included in the price, so there is nothing extra to pay on delivery.
If you need your order quicker than this, please send us an email or start a chat on our website and we'll do our best to accommodate.
Where is the Sunday Light made?
Every Sunday Light is handmade to order in our London workshop.
Where can I see a Sunday Light in person?
Private viewings are available by appointment at a small number of locations across the UK, Europe and the US. Availability is limited.
The quickest way to arrange one is to book a 15 minute call and we'll find the closest option for you. Current locations are listed on our contact and viewing locations page.
Installation and delivery
How difficult is the Sunday Light to install?
Installation is no more difficult than a typical chandelier of the same weight. It fixes to the ceiling and wires into a standard supply, and any qualified electrician can do it, typically in 1-2 hours.
Does it work with US and international electrics?
Yes. Sunday Light runs on any mains supply from 110-250V at 50 or 60Hz, so it works in the US, Canada, the UK, Europe and beyond. No transformer or converter is needed, and it wires in like any other ceiling light.
We can also arrange installation for you in New York, Los Angeles, San Francisco, Seattle and London, and every light ships with all duties and taxes included in the price.
Can you arrange installation, and what does it cost?
Yes. Add professional installation when you order: $450 in New York, Los Angeles, San Francisco and Seattle, £450 in London, within 25 miles of the city centre. A qualified local electrician fits your light, arranged by us, and you have a full refund available any time before installation day. See what's included.
Elsewhere, any qualified electrician can fit the light in 1-2 hours. Email us and we'll see what we can arrange in your city.
Is Sunday Light water-cooled?
Yes. Sunday Light uses a sealed, water-based cooling system to support its uniquely high light output (34,500 lumens) while staying quiet and comfortable for long use.
The cooling loop is fully sealed and self-contained, with no plumbing and nothing to top up or maintain. Water cooling is what lets Sunday hold daylight-level brightness continuously.
Does the light require plumbing in?
No plumbing is required. The water-cooling loop arrives prefilled with distilled water plus corrosion and anti-bacterial inhibitors. The system is fully sealed and requires no topping up or maintenance.
The installation process is the same as installing a chandelier and typically takes 1-2 hours.
How heavy is it? Will it work on my ceiling?
Around 22kg, fixed to the ceiling at two points, like a chandelier of similar weight. We've installed across all sorts of ceilings, including concrete and plasterboard.
Sunday Light installs in almost all locations with ceiling height above 240cm (94 inches). Please email us if you have any concerns about your space before ordering.
Still have questions?
We're here to help. Reach out to our team and we'll get back to you as soon as possible.