how to mimic sunlight indoors

Looking for a guide to simulate sunlight indoors? You’ve absolutely come to the right place!

What if I told you there was such a thing as mal-illumination? Similar to malnutrition, it’s when you’re deprived of biologically necessary light.

Many of us spend large portions of our day completely disconnected from natural sunlight. In the winter months, we may even go entire weeks without spending a moment in the sun!

Instead, we bask in man-made light spectrums that pay no heed to our ancestral origins or biological needs.

These spectrums often have wildly unnatural visible wavelength ratios and are completely lacking all beneficial infrared and ultraviolet wavelengths. Not to mention, the dimness that often accompanies these environments is an issue all its own.

This is obviously untenable if we hope to stay functionally healthy for a long period of time. Human beings need full-spectrum light exposure for optimal health.

Full-spectrum sunlight is necessary for optimal eyesight, digestion, sleep, movement, repair, and detoxification.

Of course, since we spend a large portion of our time inside structures that block most of the natural light from the sun, we must consciously work to bring these missing spectrums back into our indoor spaces.

If we hope to emulate it, let’s first go over just what sunlight is.

The Qualities of Natural Light

The only natural source of radiation comes from our Sun, and all life on Earth has adapted to this form of energy over the course of billions of years.

What is Sunlight Made Out Of?

Let’s start with the spectral makeup of natural light so that we can better conceptualize what we need to copy.

Below is a spectral distribution graph of sunlight as it passes through the atmosphere.

a spectral graph of sunlight before and after it passes through the atmosphere
The full spectrum of sunlight as seen on Earth. (Source)

This can be broken down into roughly the following percentages:

  • UVB: <1%
  • UVA: 8%
  • VIS: 44%
  • IRA: 32%
  • IRB: 14%
  • IRC: 2%

As you can see, most of the energy coming from the sun is in the visible band, and it’s fairly even across the board; although there’s usually a slight bump in the blue-green area throughout most of the day.

There’s also a fair amount of UVA and tons of infrared energy in sunlight.

The Color of Sunlight

The appearance of sunlight changes throughout the day in relation to the amount of high-frequency light it contains.

The color of sunlight and all artificial sources of light are expressed in Kelvin, or the apparent “color” of a heat source. As the heat source rises in temp it becomes “cooler” in appearance.

image of sunlight color temperature changes throughout the day from morning to night
To give you an idea of how the color of sunlight changes throughout the day. (Source)

The color temperature of sunlight in space is about 5900K, but by the time it reaches the earth on a clear summer day, this dips down to about 5200K to 5700K due to the Rayleigh scattering of the shorter wavelengths, hence the blue sky.

gif of the spectrum of sunlight changing throughout the day
The spectrum of sunlight as seen in Michigan, March 28th, 2022 using a SEKONIC C-800. The weather was partly cloudy, but all readings were of direct sunlight.

As you can see, throughout most of the day (9AM – 6PM) the color temperature of the Sun was between 5000K and 5700K.

And below is a minute-by-minute spectrograph capture of sunlight from 7 am to 12 pm for an idea of how sunlight changes during sunrise.

When it comes to choosing artificial lighting, you’ll be looking for lights that correlate with this trend by choosing something >5000K for the daytime, and <3000K for the evening.

representation of color temperature from various lights from 2000k to 10000k
Various light sources and their color temperatures.

Natural Light is Bright and Powerful!

One of the most important aspects of natural light is that it’s very bright!

The radiation hitting the Earth at the equator peaks at about 1,120 W/m2. Over the course of a year, this averages out to around 340 W/m2.

a graph of the variation in solar intensity in W/m2 over the course of a cloudless day at the equator
Variation of equatorial solar intensity on a cloudless day.

All of this power culminates in a very bright source of light, with sunlight producing about 93 lumens per watt. Meaning, at equatorial noon we should see about 104,160 lux (lumens per square meter).

If we averaged an entire year over all locations on the Earth’s surface, the average solar irradiance would be about 170 W/m2 per day and about 16,000 lux. These change based on the specific area, if we’re in cloudy Scotland, the year-long daily average is closer to 72 W/m2 and about 7,000 lux.

As you can see, the Sun is a powerful, bright radiating machine, and the brightness of our indoor environments usually pales in comparison.

lux levels from various indoor and outdoor environments
Lux levels from various indoor and outdoor environments. (Source)

One of the most beneficial things we can do for our health is to simply increase the brightness of our interior lighting.

This can be done in a number of ways, which we will go over. However, know that at this time it’s generally quite expensive to drastically increase the lux in your home using high-quality LEDs.

My Thoughts on Lux Levels

I think it’s probably more important to increase the lux levels in a room than it is to fill a room with high-quality, yet dim light.

The average room is maybe 500 lux if you’re lucky, while on an average clear day, it’s 60,000+ lux outside at eye level.

There’s easily 120x more energy entering our eyes and skin when we’re outside.

This massive decrease in energy, when we go inside, is what leads to mal-illumination.

Is it any wonder everyone complains of bad sleep and poor energy?

And the severe lack of infrared energy hitting our cells is contributing to metabolic dysfunction in just about everyone.

So we’ll go over some of the various ways to increase the lux levels in your most occupied spaces.

Light Flicker

Artificial lights, for the most part, flicker at various frequencies due to the alternating current powering them.

The sun, on the other hand, stays at a very steady brightness throughout the day.

Once a light’s flicker rate reaches a certain threshold, called the critical flicker fusion rate, the human eye starts to see it as one average brightness.

But! Just because we can no longer visually perceive it doesn’t mean it’s gone. What we’re left with is termed “invisible flicker”.

Now, this invisible flicker comes in many styles. Some lights flicker at 120hz or 120 times per second, just outside of our perception, while others flicker at 10,000hz and beyond.

And some don’t flicker at all, much like sunlight.

The question is, does this invisible flicker matter? It is invisible after all.

And surely humans have some adaptation to flickering lights, right?

Think of tree canopies shifting in the wind or running through the forest. Or dancing firelight.

However, if you peruse a website like, you’ll see that there are many people who seem to suffer in the presence of invisible light flicker. Perhaps they’re the canaries in the coal mine?

The IEEE has set an optional industry standard for flicker with Std. 1789. They looked at all the available data and created a rough guide for flicker safety.

It looks something like this:

line graph dispalying the IEEE PAR 1789 flicker safety standard showing where the percent of flicker and Hz become high risk
IEEE Flicker Percentage vs. Hz (Source)

However, it should be noted that these are just best guesses at this time, as the science of invisible flicker is very understudied.

Either way, the suggestions we have later in the article will include these metrics, so you can avoid these issues if you feel it’s worth it to you.

How to Get More Natural Light Indoors

Now, before we begin adding artificial “sunlight” to our homes and offices, let’s make sure we’ve done everything we can to let in real light first.

1. Let the Light in!

Let as much light in as you can by opening your blinds and windows. If you have an issue with glare, it would be better to apply anti-glare film than to cover the window with curtains or blinds.

If only a portion of your window is the trouble spot, you can choose to apply a small portion of the anti-glare film, so that more light can get through the rest of the window.

2. Get as Close as You Can

Wherever you spend most of your time, most likely in your office or family room, make sure it’s near a window. At work, try to get a location nearest a south-facing window, east would be second best.

3. Hardwood Floors are Better than Carpet

Hardwood floors will reflect more light into a room than carpet will, and light floors will reflect more than dark. Something to consider for future renovations?

4. Selecting Paint Colors

Wall color hues with more white in them (think lighter) will reflect more light around the room. Go with a satin variant here to maximize reflections without making imperfections too obvious.

Since north-facing areas of the house will get bluer light, you can paint warmer hues there, while south-facing windows will receive warmer light and could stand to be painted cooler colors.

This will help even out the colors reflected into the house into a more even color tone.

5. Add Privacy Window Film

If privacy is a concern with certain windows, try applying window film. This will allow you to feel secure while still allowing sunlight in.

Frosted Window Film

window film product photo

Rabbit Goo is my favorite window film brand, just clean your window, apply some water, and squeegee that sucker on there.

The Science Behind Full Spectrum Visible Light

Visible light is the portion of sunlight responsible for setting your circadian rhythm, meaning it’s the most important part. If you choose to implement only one part of the spectrum of sunlight, this would be the one.

The beneficial effects of bright full spectrum light are too numerous to count.

This is a resource section for anyone who wants to explore the science a bit more or needs some intellectual ammo at work for why you want to change your lights.

  • A Literature Review of the Effects of Natural Light on Building Occupants cites hundreds of examples of bright full-spectrum light being beneficial in every scenario imaginable. [R]
  • Ambient lighting brightness appears to be very important for proper refractive development in young animals, with dim light being significant in myopia development. [R]
  • Exposure to sunlight and ultraviolet light is associated with a decreased incidence of myopia development. [R]
  • Bright ambient lighting retards the development of form-deprivation myopia in monkeys. [R]
  • Recovery from form-deprivation myopia in chicks was significantly better under full-spectrum LEDs when compared with fluorescent light of the same color temperature. [R]
  • In a study of 27 children, the majority had better eyesight under a 5500K color temp light vs 3600K. [R]
  • Time spent outdoors in bright sunlight reduces the chance of developing myopia. [R]
  • Bright light exposure at home is associated with less sleep disturbance, anxiety, stress, and depression. [R]
  • In a group of call center workers, switching from a low CCT light source (2900K) to a high CCT (17000K) resulted in improvements in well-being and work performance. [R]
  • Bright light sufficient to trigger a circadian response improves sleep, mood, and behavior in dementia and Alzheimer’s patients. [R]
  • In this study, hens preferred spending time under bluer fluorescent lighting over incandescent light of the same lux. [R]
  • In a study involving 313 workers, exposure to more full-spectrum sunlight resulted in 63% fewer headaches, 56% less drowsiness, and 51% reduced eyestrain. [R]
  • Evening melatonin secretion and peripheral heat loss occur earlier in office workers exposed to brighter light. [R]
  • Exposure to adequate amounts of blue light is necessary to set the circadian rhythm and bring about a massive cascade of biological processes on a daily basis. [R] [R]
  • High energy wavelengths like blue light can cause retinal damage, it’s important that lighting is bright enough and even across spectrums so that the retina is properly dilating. [R]
  • Diurnal rats lose about 30 percent of hippocampal capacity and perform far worse on spacial tasks after four weeks in dim light. [R]
  • Workers near windows had higher melatonin levels and lower cortisol at night compared with workers who weren’t near windows. [R]
  • Psychologically and physiologically unwell hospital patients seem to recover faster when exposed to sunlight. [R] [R] [R] [R] [R]
  • In elderly patients with major depressive disorder, bright light therapy improved mood, sleep efficiency, and cortisol levels. [R]

Lights that Mimic Natural Sunlight

Now onto the practical portion of this guide!

What we’re going to try to do here is the following:

  1. Increase the brightness at eye level to at least 1,000 lux, really the higher the better, it should be ambient and comfortable light ideally coming from overhead.
  2. Accomplish this using full spectrum high-quality LED lights if possible.
  3. Include UV and infrared lights to round out the other parts of the spectrum that are missing.

Use this lumen calculator by Waveform to figure out how many lumens you’ll need per room to achieve 1000 lux. For this, enter your room dimensions and set the fc value to 100 fc which is equivalent to 1000 lux.

The only way to reliably mimic the visible portion of sunlight is with LEDs. Now you might be thinking, but Derek, LEDs suck. And you’d be right, except they don’t anymore. (kind of)

Historically, LEDs obtained their “cooler” color with the dreaded big blue spike. However, newer LED phosphor technologies have made these classic LED problems a thing of the past.

generic low cri led spectral power distribution graph
yuji crimax 5000k a19 spectral power distribution graph
ge sun filled 5000k br30 spectral power distribution graph
Full spectrum LED

What we’re left with instead is an impeccably realistic color spectrum, that feels natural and energizing!

Unfortunately, the pickings are rather slim. Hopefully, with time more companies and manufacturers get in on the full spectrum LED game.

The Best Full Spectrum Light Bulbs

Some of the best LED light bulbs spectrum-wise are made by Norb. They offer two premium lights at 4000 and 5000K that are good-looking lights.

  • Learn more

Check out our post The Best Full Spectrum Lights for more info on this topic!


norb smile product image
  • Lumens: 800
  • CCT: 5000K
  • Watts: 11w
  • Shape: A19
  • CRI:
  • R9:
  • Dimmable: Yes
norbsmile 11w a19 spectral power distribution graph
Spectral power distribution graph
norbsmile equal luminous flux graph
Sunlight comparison graph
norbsmile 11w a19 flicker Risk graph
Flicker risk
norbsmile 11w a19 waveform Graph

NorbSMILE Soft

norb smile soft product photo
  • Lumens: 800
  • CCT: 4000K
  • Watts: 11w
  • Shape: A19
  • CRI: 98
  • R9: 93
  • Dimmable: Yes
norbsmile soft 11w a19 spectral power distribution graph
Spectral power distribution graph
norbsmile soft Equal Luminous Flux graph
Sunlight comparison graph
NorbSMILE Soft 11w A19 flicker Risk graph
Flicker risk
NorbSMILE Soft 11w A19 waveform Graph

They also have a couple of more budget-friendly lights that cost a bit less for those on a budget.


norb everyday sun product photo
  • Lumens: 800
  • CCT: 5000K
  • Watts: 9w
  • Shape: A19
  • CRI: 89.9
  • R9: 94
  • Dimmable: Yes
normsile everyday sun 5000k a19 spectral power distribution graph
Spectral power distribution graph
norb everydaysun equal luminous flux graph
Sunlight comparison graph
norb everyday sun 5000k a19 flicker Risk graph
Flicker risk
norb everyday sun 5000k a19 waveform Graph


norb everyday sun soft product photo
  • Lumens: 800
  • CCT: 4000K
  • Watts: 9w
  • Shape: A19
  • CRI: 92.3
  • R9: 99
  • Dimmable: Yes
normsile everyday sun soft 4000k a19 spectral power distribution graph
Spectral power distribution graph
norb everyday sun soft equal luminous flux graph
Sunlight comparison graph
norb everydaysun soft 4000k a19 flicker Risk graph
Flicker risk
norb everydaysun soft 4000k a19 waveform Graph

My next recommendation is the premium one.

Yuji is a company that takes great pride in the quality of its lights, from the diodes themselves to the internal components such as drivers and capacitors.

This results in the only zero-flicker full spectrum LED bulb available on the consumer market.

If you’re looking to fill your home with lifelike light indistinguishable from the sun, Yuji is the way to go!

Yuji SunWave


Zero flicker, excellent sunlike spectrum, and great build quality make these our favorite premium light bulbs.

  • Lumens: 1100
  • CCT: 3000-6500K
  • Watts: 11w
  • Shape: A19/BR30
  • CRI: 95.3-97.7
  • R9: 92-97
  • Dimmable: Yes
yuji sunwave 6500k a19 spectral power distribution graph
Spectral power distribution graph for 6500K model
yuji sunwave 6500k equal luminous flux graph
Sunlight comparison graph for 6500K model
yuji sunwave 6500k a19 flicker risk graph
Flicker risk
yuji sunwave 6500k a19 waveform graph
Waveform graph

Use code OYBYJ5 for 5% off!

Now an interesting light bulb that’s quite a bit more affordable than both of the options above is the newer Philips Ultra Definition bulb.

These lights have kind of a funky spectrum, but they’re very high CRI and while they do have a large red spike, there’s no large blue spike or turquoise dip which I like, and the flicker on these is usually pretty good too.

Philips Ultra Definition

philips ultra definition product photo

These are the best budget-friendly full-spectrum lights on the market right now.

  • Lumens: 800
  • CCT: 5000K
  • Watts: 8w
  • Shape:
  • CRI: 94.7
  • R9: 90
  • Dimmable: Yes
philips ultra definition 5000k a19 8w frosted spectral power distribution graph
Spectral power distribution graph
philips ultra definition a19 5000k 8w frosted bulb equal luminous flux graph
Sunlight comparison graph
phillips ultra definition 5000k a19 8w frosted flicker Risk graph
Flicker risk
phillips ultra definition 5000k a19 8w frosted waveform Graph

One last recommendation would be the 15w bulb from Sylvania’s Natural Series. As this version in particular has the best spectrum and flicker of the ones I tested.

Sylvania Natural 5000K 15w

sylvania natural product photo

The best light bulb the Sylvania Natural series has to offer. A pretty nice spectrum that’s lacking a bit in the red department.

At $5 per bulb, this is one of the best full-spectrum high-lumen lights on the market!

  • Lumens: 1600
  • CCT: 5000K
  • Watts: 15w
  • Shape: A21
  • CRI: 87.3
  • R9: 46
  • Dimmable: Yes
sylvania natural 5000k a21 15w frosted spectral power distribution graph
Spectral power distribution graph
sylvania natural 5000k a21 frosted 15w Equal Luminous Flux graph
Sunlight comparison graph
sylvania natural 5000k a21 frosted 15w flicker risk Graph
Flicker risk
sylvania natural 5000k a21 frosted 15w waveform Graph

You can check out more of the lights we’ve tested by visiting our database below!

light bulb database button

The Ultimate Ceiling String Light

I recently built a giant strong light fixture for about that puts out around 45,000 lumens of full-spectrum, flicker-free light throughout my dining room, living room, and kitchen.

photo of ceiling string lights setup
It’s absolutely marvelous.

This gives you the ability to spread the light out over a larger surface area, making it less glaring to increase the total lumens in a room.

To create this I bought a white string light fixture with 8 sockets. I recommend white since it blends into the ceiling much better than black.

I attached this to my ceiling with small screw hooks and drilled tiny pilot holes for them.

Then I plugged 8 of these 7-in-1 splitters into my string light fixture so that I could fit 56 lights which is right around the wattage of this string light.

  • Caution

These 7-in-1 splitters are not UL-listed. So look it over before using it. Make sure the socket screws are all tightened and that the wire nuts under the main housing cylinder are tight.

For the bulbs, I went with these Philips Ultra Definition lights. they’re pretty affordable, offer a nice high CRI spectrum that’s fairly natural, and have a low flicker.

Unfortunately buying 54 really high-quality lights like Yuji Sunwave would require shelling out a ton of money.

For convenience, I bought this RF outlet and mounted the switch on the wall next to my kitchen lights.

wireless on off switch photo

It basically feels like a permanent light fixture!

The end result is bright, comfortable, and looks pretty decent actually, not as much of an eyesore as I thought it might be.

This has made a huge difference for us in the winter. Altogether it cost about $300 and has been well worth it.

The DIY Chandelier

Here’s another thing I’ve done…

You can create your own hanging chandelier, the same hooks as above can work here too.

Though more than one would be ideal, we really want to pump those lux numbers up.

You may want about three or four of these in a room to really increase the lumens.

DIY Chandelier

DIY chandelier with six ge sunfilled light bulbs and a single halogen

Here is a DIY chandelier using six GE Sun-Filled bulbs and a single 72-watt halogen for infrared coverage. This setup costs about $100 and provides approximately 6370 lumens.

This could be done using any combination of lights.

spectral distribution graph of diy chandelier

Desk Lighting

Okay, so what about those of you who have a work office and want more light all up in those eyeballs?

Various lamps, extenders, and fixtures can be utilized to provide point-of-use lighting.

These kinds of setups can obviously risk introducing glare, meaning the light source stands out too much from the ambient light, causing discomfort. Getting the lights above eye level and further from your screen helps.

Even just one BR30/40 pointed toward you during the day could have a really positive impact on your mood, sleep, and overall well-being.

I’m currently working on a DIY over-the-monitor glare-free high-lumen desk light that should hopefully be cost-effective and easy to build, I’ll update this section once it’s done!

High Lumens on a Budget

One more option, while not perfect (none of them are really) is to utilize super high lumen output flood lights or high bay lights in your home.

UFO High Bay Lights

These lights can put out 300w of light or 30,000 to 40,000 lumens for around $80.

So if you’re on a budget and want lots of light for a little money, this is the way to go,

high bay light
300w high bay light

Those who suffer from seasonal affective or sleep disorders may benefit substantially from dramatically increasing the lumens in their occupied living areas.

While the light these put out isn’t ideal from a quality standpoint, you likely stand to benefit more from high lumens, than high-quality low-lumen light.

I haven’t played around with these personally yet but I plan to buy several soon and test them out so that I can recommend the best ones.

In the meantime, if you have the budget for it Yuji sells basically the only high CRI UFO high bay light I know of:

Yuji 200W High Bay Light

yuji high cri ufo light product photo

This Yuji light can be ceiling mounted right above your workspace and produces very high-quality light.

It’s flicker-free and dimmable, and you can even get an option motion sensor.

Both 4000K and 5000K versions are available.

Use code OYBYJ5 for 5% off!

You should be able to mount these “upside down” using plant hangers. This will give you a very dispersed ambient light effect without any risk of glare.

Garage Lights

Very similar to UFO high bay lights, garage lights can be bought for very cheap and output tons of lumens.

These also have E26 connectors making them easy to install in your typical light socket.

garage led
200w garage light

The arms on these lights can be titled to point to the side rather than directly down if you want to create a more ambient light effect.

Similar to the UFO lights, I haven’t gotten my hands on a sufficient number of these to find the best ones yet.

Mimicking Full Spectrum Infrared Light

The next step in our replication of sunlight is to bring infrared back into the game.

Infrared light is of course very famous right now as red light therapy and is useful for a number of reasons. However, most of us go entire days without getting any IRA or B on our skin, and that is just no bueno.

The Science Behind Full Spectrum Infrared Light

Why is infrared light so beneficial and necessary?

  • Red and infrared radiation penetrates the deepest into the body and helps mitigate the stress response from short wavelength blue, violet, and UV exposure. [R]
  • Morning exposure to red light improves eyesight in older people, afternoon exposure however did not seem to have the same effect. [R]

One of the best ways to introduce infrared into your environment is with tungsten filament lights.

Technically, the Sun contains a quite bit more IR-A than IR-B and very little IR-C. While tungsten filament bulbs contain proportionately more IR-B and IR-C than the sun.

pie charts comparing the ratios of visible light, infrared, and ultraviolet light in sunlight versus halogen lamps
A breakdown of the Sun’s energy spectrum compared to a halogen light source.

Now, this graph is now completely accurate, because halogen bulbs actually burn hotter than regular incandescent and thus emit more visible light, hence their more “efficient” label.

Check out the difference between an incandescent and a halogen at around the same wattage:

ge 43w halogen spectral power distribution graphsunlite 40w incandescent spectral power distribution graph

You can see that the halogen gas allows the halogen bulb to run a bit hotter, and thus emit more visible light at the same wattage.

The image below shows the general curve trend of sunlight compared to one of these tungsten filament lamps.

graph comparing infrared spectrums of sunlight and incandescent
As you can see, resistive lighting contains a plethora of energy in the healing infrared spectrum. However, it also contains far more far-infrared than sunlight.

What the image above is missing is the absorption bands of water. Because as sunlight passes through the atmosphere, water droplets in the air absorb much of the infrared.

a graph displaying the absorption bands of water in sunlight and water-filtered infrared
The yellow line is the spectrum of halogen light being passed through 10mm of water. As you can see it removes almost all of the IR-B and C. There are also some parts of the IR-A band that are naturally reduced as well just as they are in sunlight.

So, if you want to get really nerdy, you have to filter your infrared with water. What you’re left with is called wIRA or water-filtered infrared A.

This kind of infrared is used medically in devices like the HydroSun, as the smaller amounts of IR-B and IR-C prevent the skin from overheating, and allow for higher doses of IR-A which penetrate much deeper into the skin.

It’s basically impossible to purchase such a wIRA device at this time, so I’m trying to figure out how to make an easy-to-build DIY device.

Once I have something to report on that, you’ll be the first to know!

If you sign up for my newsletter that is.

But for now, I think regular old halogen is gonna be okay.

Strategies for Infrared Coverage

Here are a few ideas for you to try out and customize to your spaces.

The Three-Arm Lamp

three arm lamp with three halogen BR30 bulbs in it

The three-arm infrared lamp. This uses three 53-watt BR30 halogen lights and puts out a pretty comfortable warmth at about two feet. It’s perfect for use at a standing or sitting desk, and each lamp can be manipulated and turned on or off as needed.


For larger areas, and for a bit more throw, you can use high-wattage heat lamps.

After having this setup for about a year, I love it!

The Big Boy

heat lamp shining down on kitchen area from cabinets

Since the clamp lamp itself has no switch, I chose to use a motion sensor plug with a 24-hour mechanical plug. This way, from 6 am to 8 pm, the light automatically turns on while we’re in the kitchen! It’s great. These can be set to turn off if no motion is detected for 2/5/… mins.


And if you’re looking for a good general-purpose infrared bulb to include in your visible light setups, grab a 72w halogen. These probably won’t be around much longer due to changing energy laws get them while you can!

Frosted Halogen Lights

frosted halogen product photo

Frosted glass is the way to go my friends.

  • Lumens: 1270
  • CCT: 2900K
  • Watts: 72w
  • Shape: A19
  • CRI: 99.3
  • R9: 97
  • Dimmable: Yes
ge 72w halogen spectral power distribution graph
Spectral power distribution graph
ge 72w halogen equal luminous flux graph
Sunlight comparison graph
ge halogen 72w flicker risk graph
Flicker risk
ge halogen 72w waveform graph

Mimicking the Ultraviolet Spectrum

Finally, we have ultraviolet light, and yes, it too is an important part of sunlight! Believe it or not, both UVA and UVB penetrate the atmosphere all year, even in high-latitude areas in the winter.

The reason it’s often said that you can’t make vitamin D in the winter is just that there’s much less UVB, and you’re always wearing clothes. But it’s still there.

The Science Behind Ultraviolet Light

Our bodies have adapted to utilizing UV radiation for a very long time.

We of course need UVB and UVA to make vitamin D in the skin, as well as some other things, so I think it’s a good bit of common sense to put a healthy amount of UV in our homes.

As I mentioned earlier in the guide, natural sunlight gets as strong as around 20:1 UVA to UVB, so we’ll want to try to match that the best we can.

The Best Ultraviolet Lights

The best UV lights are currently fluorescent in nature, LEDs that produce wide-spectrum UV are recently gaining a bit in the reptile space, so it might not be too long before we see decent LED options, they just aren’t here yet.

And so fluorescent it is.

Fluorescent lights contain trace amounts of mercury and other toxic metals. Be careful not to break them, and if you have children who throw things, you may want to purchase a cage for your light.

Safety Warning
  • Arcadia 6% UVB Lamp: This is probably one of the best UV lighting options out there currently. It provides a ratio of 5:1, which clearly isn’t 20:1, but at a low UV index I don’t really see this being a huge deal, I would certainly consider it better than no UV at all. The ballast used in the Pro T5 Kit is a high-frequency electronic ballast, so there’s no flicker and very low EMF exposure, unlike the old magnetic ballasts some of you may be familiar with.

Arcadia 6% UVB Lamp

arcadia uvb light product photo
  • Lumens: 1270
  • CCT: 7000K
  • Watts: 54w
  • Shape: T5HO
  • CRI: ~
  • R9: ~
  • Dimmable: No
arcadia 6% uvb lamp spectrum graph
Spectral power distribution graph from Arcadia

Coming soon!

How to Implement

The best way I know of to add ultraviolet into your indoor space is by mounting a T5HO tube lamp in the corner of a room’s ceiling.

These can be added to any number of rooms where large amounts of time are spent.

TIP: Fluorescent UV bulbs should be replaced every year or so, as the UV output fades with use.

flourescent tube light mounted on ceiling crown moulding
This is a 46″ T5HO fluorescent light bulb mounted on ceiling crown molding. It’s recommended to cage these if you are worried about a child potentially causing damage.

The UV index for this light setup is as follows:

1 ft: 3.5 UVI
2 ft: 1.5 UVI
3 ft: 0.8 UVI
4 ft: 0.5 UVI
5 ft: 0.2 UVI

Measuring Light

Here’s a collection of various tools for measuring your light environment, before moving forward, you may want one or two of these.

  • Opple Light Master Pro 3: This little thing is unbelievable for the price! If you want to test your own lights look no further! This will give you lux, color rendering index (CRI), flicker, color temperature (CCT), and more! All for less than $50, crazy awesome device.
  • Solarmeter Model 6.5 UV Index Meter: You’ll probably want one of these if you plan to incorporate a UV bulb into your sunlight spectrum setup. This way, you can ensure you won’t be exposed to unnaturally high levels of radiation.
  • Handheld Digital Light Meter: This is a fun tool to have on hand if you’re looking to emulate the brightness of the sunlight in your area. It’s also just a fun tool for curious-minded folks.

TLDR: Action Steps

This section is for those of you who either don’t have time to connect all the dots above or just want a quick list of things that can be done to optimize your biology.

  1. Ensure that the indoor environments in which you spend the most time have adequate circadian light, i.e. >500 total lux, ideally >1000 lux. This can be done with any lux meter.
  2. Purchase full spectrum LED light bulbs of 5000K or greater for daytime use in your home and office, and purchase or create fixtures that will allow you to achieve a high level of lux. NorbSmile is a great option.
  3. Set up full-spectrum infrared lighting by using either incandescent heat lamps or BR30/A19 halogen bulbs.
  4. Bring healthy UV into your space by mounting a reptile T5 fluorescent light in your most occupied area(s).

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  1. I’m planning on trying this set up for my bedroom minus the UV fluorescent light.

    My only concern is that it will look too ‘cold’ in my room, if that makes sense. It’s hard to tell by your picture but do you think the GE Sun Filled lights would be appropriate lighting for a bedroom. I’d like it to still feel welcoming in there.

    My current set up is Philips Hue’s installed in the ceiling sockets that automatically dim and go down to around 2000K 1-2 hours before I go to bed. Seeing as the only automated lights to mimic that would be the LEDVANCE Tunable Smart Lights which are only available in Europe, the next best thing I can think of would be to install a smart switch that dims the GE Sun Filled bulbs around the same time.
    What do you think of this compromise?


    1. Hmmmm. I’ve thought about the same thing. I tend to use the 5000K GE unfilled in rooms I spend during the day only.

      What sets apart the GE from most other 5000K options is there have a lot more of the longer wavelength red light in them, which helps them avoid feeling artificially “blue” like other 5000K lights. They are however bluer than anything lower than 5000K, obviously.

      For evening/night they might not be a great option, though you definitely could do it! I like to use 2700K versions and dim those. (used in a lamp), or really dim incandescents that come out to closer 2000K. As at night I really like very dim light.

  2. Hi there,
    Great article –
    Quick question – there seems to be no mention of Waveform Lighting who I thought were the main player in this space (IE full spectrum sunlight mimicking bulbs).
    Was this a deliberate omission?
    Did you research them? What chips / diodes do they use?

      1. Wow, thanks for linking the test result doc! Incredible job putting that together – must have taken a huge amount of time and effort (not to mention cost). Excellent work.

          1. Hey Derek, another quick question if you don’t mind-
            For the Taobao Shanpu ZPro, what base do they come with, ie B22, E26, E27?
            There doesn’t seem to be an option to select that anywhere, and the description doesn’t seem to mention this either.

  3. Hi Derek,

    Great job on the article. I’m looking forward to implementing these solutions for myself.

    I’ve been reading about Tuo ( It appears to signal the circadian rhythm at least as strongly as high lux lighting you’ve described in this article. Do you feel bright lighting has some added benefits compared to a smart bulb like Tuo?

    I’d also be interested about your personal experience with your light setup. Do you feel / sleep better?


    1. Hey David! First I’m hearing of Tuo, they certainly use a lot of buzzwords in their “our science” section, but don’t provide any real data. They claim to have performed a study in which their bulb caused a larger circadian shift when compared toa “blue” light at similar lux levels. But without knowing the specific spectrums or being able to see the actual study (which I cannot find), it’s hard to say what this means.

      Perhaps I’ll buy one and test it out! Looks like they offer a free 30-day trial 😉

      I’ll be doing a new in-depth light bulb test here soon with some new bulbs and perhaps I can include this one in the mix.

      I already slept quite well, but I definitely don’t sleep any worse! I love it in the mornings, really wakes me up.

      Thanks for the link!

  4. Another amazing piece of work so well researched and thought out – thanks for sharing all that info. I built a wood cabin in my garden and faced it south so most days get some glorious real sunlight which lifts me and heats the place up nicely. I am just about to rx my UVB sperti lamp so will update folks on here about my results on that.
    One wish I have for everyone here is that this generation and others will realise the fraud that is pharma/medical science and start to be their own health detectives and directors. Its almost if the Pharma crowd want us lead in the wrong direction with health. If I have learned only two things all the last 30 years of health study and that is the importance of Vitd status and the macro minerals. I would guess conservatively that 90% plus of all disease is a function of the above. Meanwhile conventional medicine is telling us to avoid the sun wherever possible and processing foods and depleting the soils of minerals. OK rnt over – blessings to everyone!

    1. Haha thank you Tim! And amen to that brother!

      My home office gets sunshine in the morning and it’s a glorious thing.

      That’s what I’m hoping to do with this website, is give me people the real tools and information they need to become their own health practitioners. Because unfortunately the current medical model just isn’t set up for people interesting in true vitality.

      We’ll get there slowly but surely!

  5. Hi Derek, great article! I have a few questions that I still struggle to find answers and would really appreciate it if you took the time to answer them 🙂

    1) If I achieve 5k+ lux of full-spectrum light in my home office, is there any point in also buying SAD lamps/glasses like Luminette to mimic morning sunlight?

    2) In March, Yuji will start shipping SunWave series lights with extended red spectrum ( and Well24 series with cyan boost ( However, the price is crazy at $140+tax+shipping for four 700/1100lm bulbs. Seems like a terrible deal?

    3) Any benefit using heat lamps over regular incandescent/halogen? More infrared and less visible light output?

    4) Since you can’t get full-spectrum bulbs in the EU region besides Ledvance sun@home, I’m thinking of DIYing a pendant light with a couple of Bridgelux Thrive BXEB-L1120Z-50S4000-C-C3 (18$ per 5400lm strip). My question is, where should the strips be pointed: up, down, or up&down (direct+indirect)? Currently, I’m thinking of getting this:

    1. Hey Mike!

      1. It would technically depend on the spectrum and lux at eye level, but that’s definitely enough to have a circadian impact. I’d say if you have health problems or sleeping issues or are just looking to improve sleep, you want as much as possible obviously.

      2. I saw those! Looks like the SunWave line is already available for sale, I was going to buy some to test until I saw the price tag! Maybe I con convince them to send me some samples in the near future. I just found some new full-spectrum Chinese bulbs that look promising that should be here in the next couple of weeks that I’ll be reviewing, so maybe hold out for that, they’re much cheaper.

      3. It depends, I assume you mean a clear heat lamp rather than a red one? They’re pretty much all the same thing, just more power. So depends on where it is in relation to you. I have a big 250w heat lamp in my kitchen because I’m usually farther from it than the smaller ones in my office.

      4. If you have a crazy amount of lux output, I’d say pointing up is always best because this eliminates glare and creates a more natural feeling. However having it right above you and just to the front (out of POV) is probably best so you can maximize lux. Tough part is always maximizing lux at the eye level without creating too much glare.

      Curious how that turns out for you if you try it, bridgelux thrive definitely has a nice spectrum.

      1. Thanks for the answers, appreciate it!
        Regarding 3), I thought you can buy regular incandescent meant for illumination OR heat (IR) bulbs, either clear or red coated. Since most of the energy is converted into heat either way, infrared bulbs are probably just a marketing gimmick then.

        Regarding the pendant light, here’s my inspiration project:
        I’m still working on getting an up&down led profile that will handle 100W of strips – for the one I’ve linked in my 1st post, I was just quoted 400$ for 1 meter from my local distributor… so the search continues in China.

        Btw, another gimmick I think you’ll find amusing:

        1. Yeah, you’re right. Heat bulb I think is just more directed due to the BR30 shape they use. But you could get the same effect from a high-wattage A21 incandescent in a reflector dome or something.

          Oooof. Man good lighting sure ain’t cheap, is it? haha

          Oh wow look at that, $300 for a blue light… they don’t even list the lux or anything, good grief. Thanks for the laugh haha

    1. I’m hoping to reach out and see if I can test that at some point in the future. We’re planning on running all of the decent-looking light therapy lamps through some thorough testing to figure out which ones are actually best and I want to include the GetChroma light as well.

      1. Hi Derek, since you’ve mentioned you’ll be testing light therapy lamps, I (and hopefully you as well) would be interested in including this lamp in your testings: You can buy and return it, so it will only cost return shipping (and your time 🙂

        It’s not full spectrum (not that any SAD lamp is except for Europe-only Beurer TL95), but with the power vs cost and maybe a diffuser in front, I don’t see how it can be worse than Verilux, Northern Lights etc. stuff.

        Btw, Sansi also has a SAD lamp in their offering (, but it’s their first attempt at this and it seems to weak to have any effect.

        1. Oof yeah 18w is definitely too low for light therapy!

          Thanks for letting me know about Beurer! Wasn’t aware anyone was making SunLike light therapy lamps yet, very cool.

          I’ll test as many as I can! That’s often what we do is just pay for shipping (it’d be impossible to pay for all of this otherwise)

          I’m actually working on putting together a simple DIY light therapy lamp build that will hopefully turn out pretty well, we’ll see!

  6. Hi! Thank you for the article.

    A few questions.

    1) Why do you recommend the NorbSMILE, Philips Ultra Definition but the you use the GE?
    2) do you use any automatic setup that changes lights depends on the time of the day?

    Thank you!

    1. Hi Gabriel!

      Since I wrote this article the A19 5000K GE Sun-Filled bulbs have become very difficult to come by, so I no longer recommend them simply because for the most part they cannot be purchased, but by all means grab some if you can find them.

      Not sure why this is but they’ve been out of stock everywhere for a year or so now. If you can find them grab em cuz they’re essentially the same as the NorbSMILE just cheaper, or at least they used to be.

      As for automatic lighting, I don’t currently use any. I just change them in the evening to dimmer warmer lights. I’ve been planning to do an in depth smart light review to find the best ones, as automatic circadian lighting is pretty cool. Home Assistant appears to be the best option for this but I’ll have to look into it more!

  7. Hi Derek,

    thanks again for the article and your previous reply.

    the BR30 Halogen bulbs are discontinued. I was going to emulate your set-up, any good alternative?


  8. Great post, Derek! I work in a music studio with no windows and am trying to accomplish what you describe. Could you elaborate on measuring the lux at eye level. I’m using Light Meter LM-3000 iOS app (have an Opple on order) and get significantly different readings depending on whether I point the light meter up (horizontal), down (toward my work surface) or forward (toward my computer monitor), ranging from 190 – 480 lux.

    Also, the ambient light is very uneven. Would a Yuji 200w High Bay light at 7.5′ (ceiling height) be a good option? My space is 256 sq feet, walls are beige, ceiling is black. Already have about 14,000 lumens coming from PAR20 track lights, but probably a lot is lost to the fabric beige walls.

    I’ve also thought about putting a Yuji corn bulb in each of the 2 lamps in the back of the room but am worried that 3600 lumens at 5600K might look a little blue (Kruithof curve effect), so maybe the 3200k bulb instead?

    Finally, inspired by this video (, I’ve considered creating an artificial window using a Godox UL150 (higher extended R values than Yuji + over 56K lux at 1 meter!) along with a large parabolic reflector.

    Very interested in your thoughts and/or recommendations, and thanks for your excellent work!

    1. Hi Tom! So for the lux readings, I would just take them at eye level facing the direction you will be while working.

      The music studio definitely makes it harder with all that sound dampening! And thank you for introducing me to the Kruithof curve effect! This is something I knew about intrinsically by playing around with lights but I never knew the effect had a name. Think I’ll have to find a way to add this to the article.

      But you’re right, if you aren’t able to get enough output, cooler lights can seem too dim and blue.

      The Yuji high bay light would definitely be a great choice since it can be mounted right above you (assuming you can pull that off) and out of your FOV. Light from above is definitely the most natural feeling (and technically more effective at activating the ipRGCs) and you can get things much brighter this way before it gets too uncomfortable.

      I love that video! Such a cool project, if only we could just buy sun windows to place in our dark rooms… It’s unfortunately hard to compare the realtive output of the Yuji high bay to the Godux since one gives us lux and the other lumens. But I suspect that the high bay light might be the better option here since it will be easier to setup, cheaper, and probably more comfortable visually once it’s mounted.

      P.S. I’m currently working on a DIY light therapy lamp project which will simply be full spectrum led strips, 16″ cake/pizza pans, a diffuser, and some camera mounting hardware. I’m hoping this will be fairly cheap, desk mountable, and provide bright, comfortable light right where you need it without taking up valuable desk space. So hopefully that turns out well and might be a project you’d be interested in.

      Good luck! And feel free to update us on your solution!

      1. Thanks for your reply, Derek! Great thoughts, and much appreciated. I’ll keep an eye on your blog for the DIY project you mentioned, and will report back if/when I get to implementing a solution.

        Keep up the great work on this blog!

    1. Good question! I’ve unfortunately not been able to test any of these but they should work.

      The only con might be that they aren’t diffused at all which might be a con for some. That shouldn’t be too much of a problem as long as the light source is outside of your FOV.

      They also don’t state their lumen or lux output since that isn’t really the selling point, so it’s hard to compare them on paper to other high output options like UFO bay lights or garage lights.

      I’d have to get my hands on some and compare them, which hopefully I’ll do eventually.

      But I have seen people set these up in their house for high lumen output, it would definitely work!

        1. I think the best way to diffuse these would be to hang a fabric shower curtain liner under them. That or some muslin cloth would work great! You’ll just have to find a way to hang it, cables, hooks, rope, string, whatever works!

  9. Dear Derek,

    If you have the Solarmeter 6.5 and you’re putting a UV light near your desk area, what UV reading do you want to have if you’re holding the meter next to your chair, where your body will be most of the day? I ordered the Solarmeter after reading this article and then went to the pet store to buy a reptile light and I’m trying to figure out where to mount the light. I’m having a difficult time finding somewhere to mount the light where it won’t be in my line of vision but the meter will read something higher than zero.

    1. So the UVI where I’m sitting is pretty darn low. Maybe 0.1 and that’s at around 5-6 feet away from the light source?

      It’s off to my left side where the wall meets the ceiling. I’ve been thinking about maybe putting a Near UV light in my office just to pump up the amount of UVA, makes whites pop more and it is a normal fraction of sunlight.

      I still have to buy some and test them to find some good ones though.

      1. Thanks for replying! There are charts out there for distance and keeping your reptiles healthy, but has anyone made a distance and UVI chart for keeping a human happy during the gloomy winter months? I could go buy a swing-arm lamp and put it on the side of my desk and then adjust it to the right UVI… I just don’t know what that is.

        1. I would think a UVI of around 2 would be fairly sufficient. However it becomes a bit difficult to accurately compare the UVI of outdoor sunlight and indoor UV lights as the UVI isn’t being calculated using the same proportions. It gets a bit confusing. The best way to do it would be to use an actual wavelength spectrometer to emulate the specific amounts of UV light in proportion to the visible light.

          This paper goes over it in some depth

          John Ott was a big believer in Near UVA light “soft UV” being good for people indoors, essentially UV black lights. I’ve thought there might be something to that. It’s a relatively harmless portion of the UV spectrum that could have benefits we haven’t discovered. Most of the UV light coming from the sun is longer wavelength UVA after all.

          It’s something I need to experiment with more.

          1. Hi Derek,

            Thanks for writing back. I want to make sure you have the decimal in the right place. In your first reply, you said you have .1 while sitting 5-6 from the light source and in your second you recommended 2.

            With the reptile light I bought at the pet store, a Reptisun 10.0 UVB, the meter reads 02.0 when it is 4-6 inches from the bulb, and it’s going to be challenging to have that bulb so close while not looking at the thing.

            The goal here is to fight seasonal depression, especially as I’ve found cloudy, rainy days get me really down. I have a Verilux Happy Light and the 250W heat lamp you suggested, but I’m still trying to figure out the right setup for UV.

          2. No problem! So a UVI of 2 might be a good benchmark for a low but moderate replication of outdoor sunlight on a mildly sunny day, that’s why I mentioned it. However, the reason my UV setup doesn’t achieve this comes down to several reasons.

            1. I was initially more interested in getting some amount of UV in my office.

            2. UV emitted from a small device means that the UV bands are much smaller than on Earth. So it becomes a bit more difficult to crate larger enough “bands” that are optimally within the living space.

            This image helps visualize the point:

            UVI of reptile light

            So achieving a UVI band of 2 large enough would repair more lights, further away, essentially.

            3. Last issue you run into is UV damage. Unfortunately, more UV will inevitably cause decay and discoloration of things like plastic, fabrics, paint, etc. Now the relative output of shorter wavelengths to longer wavelengths will play a roll.

            Yeah, UV is harder to figure out. The larger 48” tube lights mounted in some tend to offer the best output. But how it’s mounted and where depends a lot on your space.

          3. Dear Derek, Update on my earlier project: I have bought a Reptisun T5 HO High Output Terrarium Hood and am intending to use it on myself for help with seasonal depression. I can tell it’s meant to sit on top of a terrarium. Any suggestions for how to mount it on a wall to point at the room?

          4. Shouldn’t be too much wiring in there. But yeah I understand your hesitance. Aside from attaching mounting hardware to it, the only other option I currently see is going with 3M command strips since the back is flat.

            I suppose you could try to create some kind of U shape bracket with something like these? Something to “sit” it into?

  10. Hi Derek, I really like the article all the info you shared it is very interesting.

    However I have doubts regarding home windows and how the light enter through the glass. I am not sure what is the best option, from what I have reading the best option would be to let enter all the possible sun-light with have window capable to filter UVA and UVB rays (most of windows only filter UVB rays, those that prevent you to burn your skin, but UVA it is all bad in the long-term).

    What do you think? Do you have any article in that regard?

    Thanks again

    1. Hi Sempere, I’m not very versed on window treatments and UV blocking.

      I don’t personally worry too much about moderate amounts of UV exposure, but it entirely depends on your bodies pigmentation abilities and your own personal preferences.

      Inside a building, some UVA will make it through windows, you’re right. However the overall UV exposure will be quite low unless your right next to the window, so if you’re not near the window, the benefit of the increased lux will far outweigh any negligible increase in UVA exposure I’m thinking.

      1. Thanks for the reply, the thing is that I am directly in front of the windows, which is great in terms of lux exposure, I am not sure if it is good to receive non-complete UV ray that are partially filtered, my guess is that it would be better to avoid any UV ray installing a filter, I have checked and there are some that are 99% transparent and will not affect the lux.

        I have another question, what devices do you recommend to use as a home spectrometer, I have checked Opple Light-master-III with it seems you cannot get the wavelength graph. Is there any budget-friendly option? The cheapest device I have found is HP350C, but it is still a little expensive for home-testing

        1. Looks like you can get an HPCS320 for around $350, that’s probably about as cheap as it gets. However there are some tutorials out there for building your own spectrometer too that would be cheaper, just requires some DIY and won’t be quite as accurate.

          But yeah if you feel like you’re getting way too much direct window sunlight a UV filter may be wise! I’m not familiar with them so I’m afraid I won’t be much help there.

  11. What an amazing article and dataset!

    I wanted to drop a comment around a new SAD light therapy lamp I found: Sunrise Sensations DayBright – it’s aesthetically pleasing and they claim to have full spectrum light with good circadian rhythm trigger – unfortunately can’t find any actual data on it and was wondering if you’ve had a go at it.

    1. Thanks Ruben!

      I have come across those actually, I agree they are nice looking, really the only type with that natural look.

      They’re on my list of lamps to test before the next moody season 🙂

    1. Those are definitely very cool! But obviously very dim for the price, if I was rich my house would have a lot of them 😂

      I’d say if you can afford them and have a place to install them go for it!