Your room can be as bright as the outdoors

November 2019

This is my first winter in Boston after coming back from Senegal. The sun sets at around 4:15 now, and it’s suddenly become extremely salient how hard it is for me to focus after dark.

I’d vaguely noticed this in the past, and dealt with it by shifting my sleep schedule earlier (or just being unproductive). But I’m waking up around 6:30 now and I already struggle to stay up for evening events. So finally, inspired by some blog posts, I decided to give up on chasing natural sunlight and make my own instead.

I bought an extremely bright “corn cob” style bulb. It emits as much light as about 40 incandescents, and produces enough waste heat that it needs an internal cooling fan to dissipate it. I put it next to my desk, in my peripheral vision (it’s somewhat uncomfortable to look at directly). According to my questionably-accurate iPhone light meter, its reflection off the curtains in front of me is brighter than the actual sunlight coming in from the outdoors (at 600 lux), and overall light levels in my interior went from 50 to 400 lux (“sunrise or sunset on a clear day”). (source).

The effect was huge: I became dramatically more productive between 3:30pm and whenever I turned off the light. Instead of having a strong urge to stop working whenever it got dark out, I was able to keep working my normal summer schedule, stopping just before dinner. I estimate the lamp bought me between half an hour and two hours a day, depending on how overcast it was.

To try to capture the difference, I used a manual camera app to take before and after photos of my desk with the same exposure and white balance. The phone camera doesn’t really capture the full effect since the dynamic range is so small, but hopefully it conveys a little bit of the amazingness:

Drag the white triangle to compare.

Everyone who’s visited my house after I installed the bulb has remarked on how cheery our living room now is, some of them before noticing the light. My partner and several friends are buying their own.

For reference, here’s the stuff I bought (note that the bulb is on sale today):

Notes:


Why doesn’t everybody do this?!

All the blog posts were written by/about people who were described as having “crippling” seasonal depression. I’ve never been depressed, which is why it took me so long to give it a try (or even notice the correlation between light and productivity).

In retrospect, that was silly. “Seasonal affect disorder” makes it sound like it’s a discrete thing that you have or don’t, but probably everyone has noticed they’re more lethargic on cloudy days. A better model might be that seasonal depression is just the tail end of a curve in how people respond to light:

Typical indoor light levels run from 100-500 lux, which at the high end is about as bright as sunrise outdoors, and about 100x dimmer than daylight. Other than “we’ve been doing it for a while,” there seems to be no reason to expect that being in a 100x dimmer environment all day wouldn’t be awful. Indoor darkness seems to be one of those things that we don’t question only because it’s been that way forever.

Until recently, though, questioning it would have been somewhat academic, because it was too expensive to buy (and power) enough bulbs to do anything about it. My bulb is an LED bulb, for which cost per lumen has been falling about 20% per year for the last 50 years (source). LEDs only passed fluorescents in efficiency recently, but they’re still dropping fast. 10 years ago a bulb as bright as mine might have cost $1,000 instead of $100.

But as of recently, it’s totally practical to fill your entire house with light that’s as bright as full daylight. Ambient daylight in the shade is about 10k lux, or 10k lumens per square meter. For a 70 m2 apartment, that would be 700k lumens. The bulb I bought is $100 for 35k lumens, so $2k would buy sunlight for the entire apartment. (In another 10 years, if LEDs don’t hit physical limits, it’ll be $200!)


To close, some ultra-bright-lamp FAQs:


  1. One HN commenter points out that this may be a problem with my house’s electrical wiring. Thanks! 

Some links in this post are affiliate links.


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Steve Bennett

I found it fascinating how different your experience from me. For instance: “but probably everyone has noticed they’re more lethargic on cloudy days” - no, those are the days I feel super energised, full of possibility etc. Whereas really sunny days make me want to hide.

Similarly “there seems to be no reason to expect that being in a 100x dimmer environment all day wouldn’t be awful” - not for me. I pull my blinds down, wish I had better curtains, and even shut my internal doors to minimise the light leaking into my study. Anyway, I love that we are all different :)

Drew

Can confirm, this is me too. I love a dark room.

teknopaul

I’m much more productive in winter months. Work best at night. I use intense white light to wake myself up, but I prefer the evenings to be like siting by an open fire: red light, low down,

Steve

Great article but yes I’ll concur with this thread - I use Philips Hue and have most of the lights fairly dim, with a candle like hue throughout winter. Great atmosphere and makes me very creative.

Ben

Same here. I find the premise completely alien. I love working at night when the bright sun isn’t inviting me outside.

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Jonathan Drkae

check out https://microsunlamps.com/how-a-microsun-works/ as I believe it is a very similar (better?) version

Ben

These look prettier, but are 1/5 as bright for twice the price.

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cdw

“cold lights”: I think there’re two things going on here. 1. People are worried about how lights will mess with their circadian rhythms, and 2. “cool color” means “blue”; “warm color” means “yellow/orange/red”. (Yes, I know this is the opposite of the actual Wien’s law.)

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Bobby

What is the CRI of the corn bulb? I noticed low-CRI LEDs are much more depressing than high-CRI lights. High CRI lights are virtually indistinguishable from sunlight.

Ben

It is allegedly 80 according to the product page–not that I particularly trust CRI measurements from random no-name Amazon sellers…

I do think a higher CRI bulb would be a pretty big improvement, but it seems to be hard to find the combination of high CRI, high temperature and lots of lumens. My coworker got excited by Yuji high bay lights but they are ~6x the cost per lumen of the bulb.

Now that the light has transitioned from “random experiment” to “expect to use forever” it’s probably going to be worth it for me though.

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Lewis Edwards

I’ve been playing with the concept of simulating daylight too. Repurposing the Fresnel lenses from old LCD screens allows you to create fake depth and a much more convincing daylight effect. Highly recommended for this type of project.

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Leo R. Comerford

See also the worldwide “epidemic” of myopia, which may be caused by inadequate light during the day during childhood. Increasing artificial lighting in classrooms is a more realistic alternative to rebuilding all of them (see also this WSJ article to which I no longer have access).

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Paul Phillips

250W for a light bulb is insane these days.

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Juhani

I live “a bit” further north, at 60 degrees.

By my experience, you do want a lot of lumen, but at the same time you do want to keep the light pleasant and soft, that means a large illuminating area. An example of such a light in action is a photography light box. To my knowledge you want a high lux, but rather low nit, that seems to be more important than excellent cri. One possibility is to point the high powered light to a (white) ceiling.

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MattGoldenberg

Has your ability to fall asleep, or sleep quality been impacted at all?

Ben

I always turn the light off when I’m done working, about 3h before bed usually. So far, that’s worked fine.

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Mo

Could you add a graph of the spectrum of non-clouded sunlight?

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kaile

Hi, there, I’ve tried your recipe this thanksgiving yet when the fixture arrived I found it was probably way too small for e39 core light bulb. How did you ever fix that into socket? (there’s noted e26 in its amazon item title)

Ben

Oh, crap–I must have used one of the adapters I bought and then forgotten about it. Sorry about that! I’ll edit the post to reflect it.

DAVID S COLETTA

The link to the adapter seems to go to something called “JESLED Non Shunted LED Tombstones - (Pack of 50)”.

Ben

Huh, no idea how that happened, but should be fixed now–thanks for flagging!

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Tom A.

Hi Ben, nice post.

I’ve spent a fair amount thinking about this and experimenting with different setups.

I prefer using (many) normal commercially available light bulbs. I think the light quality is likely to be higher, plus it gives you a bunch of flexible lights you can place where you want and move around the room. Placement is especially important because the amount of light that reaches your eye is proportional to the inverse square of the distance :).

My suggested setup comes out the same cost per lumen as yours. https://docs.google.com/spreadsheets/d/1WDsxhXzwSboOFqL7xorexY0kEb5fpLIv0ko0In87OT4/edit?usp=sharing

Always happy to chat more about this.

Ben

Yup, that’s another useful approach!

I think the main advantage of the corn bulb is easier setup (and placement, like you mention, actually–it’s easy to put the entire corn bulb 5’ from my face, and would be harder with a large mass of A19s.)

If I were doing this with bulbs, especially if I were looking for higher quality light, I’d try to find ones with a higher CRI (“color rendering index”) than the ones you listed, which are not rated substantially higher than the corn bulb. Home Depot sells many Cree bulbs sporting 90+ CRI; these are noticeably cheap but require more sockets.

Speaking of sockets, looks like these string lights achieve a total wiring cost of about $1.21 per bulb, vs $4.20 per bulb in your spreadsheet, which should drive the cost down a lot at the cost of even more diffuse light.

Tom

Do you know if it’s possible to use dimmable bulbs in a normal socket, and get the maximum brightness the bulb is advertised for?

Tom

Also, Staticman looks cool!

Ben

I’ve never verified this, but I’m pretty sure it is possible–I think “dimmable” bulbs are designed to work with dimmer switches that produce normal AC power when the dimmer is at 100%. (I currently have some dimmable bulbs in non-dimming switches, and they do not look noticeably underpowered.)

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ed

https://www.benkuhn.net/img/lux/sad.jpg

Is this created with remarkable tablet? Just wondering.

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Jared

I contacted the referenced bulb manufacturer via Amazon and they are working on making a frosted cover for this bulb that should make the light more pleasant.

They said they should have it ready in about a week.

tom

Wow, fast turnaround! So you contacted the “GE RUN” seller?

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Des

Thanks for this post, Ben. Any ideas on how to somewhat shade the light bulb as it’s hard on the eyes in plain view?

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John Willow

Hey Ben,

Thank you for this thorough blog post. I bought everything that you did and it’s on the way. However, I just saw a 26K lumen bulb that’s on sale for $10: https://www.amazon.com/dp/B07L6C6RP5/ref=cm_sw_r_cp_api_i_Fn-6DbN1A9XFK

My question is fundamentally about safety. How do I judge that bulb from a safety standpoint? It seems like a better deal but it, and the bulb you recommend as well, is seemingly sold by a random Chinese company. Is there any concern, especially given the relatively high wattage of these giant lightbulbs? Furthermore, is there any profoundly incorrect usage that you would warn against? For example, I plan on plugging the bulb into a smart outlet which is in turn plugged into a wall outlet, and I don’t know if that extra layer would pose a hazard for whatever reason. I just don’t want to start a fire. Thanks in advance.

Jon

That specific listing on Amazon looks like a pricing mistake…

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Jared Williams

Just to follow up. The light bulb manufacturer that was referenced in this post created and sent me the corncob bulb with a cream cover instead of clear. The bulb is just as bright but not as intense. It is pleasant to look at. A link to the picture they sent me when they devoloped it is here: https://imgur.com/gallery/NX8WskG . After trying it out I strongly encouraged them to sell this style on Amazon as well. I’m really impressed with the amazing customer service this company has shown so far.

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