2 Liter Bottles of Light

The slums of the Philippines are getting an extreme home makeover in the form of two liter bottles in their ceilings. The bottles function as 60-watt lights powered by 100% solar energy. Refraction is an amazing thing, if you drilled a hole in your ceiling light would drop directly through the opening in a straight line casting a shadow on the ground in the shape of the hole. By placing a bottle filled with water into the hole, the light is refracted by the water and emitted at 360 degrees like a light bulb. Light bulbs are taken for granted in America, yet are luxury item for the Philippines slums. The two liter bottles filled with water and a small amount of bleach to keep algae from growing, act as a light in the often-unlit slums.

The initiative in the Philippines to provide these lights to those who need them is known as “A liter of light”. It is estimated that each bottle light will last for about five years, which is more than any store-bought light bulb will do you for.

Its not just the Philippines who are getting on board with liters of light. Many Americans struggling with high utilities bills amidst economic woes are looking for innovative solutions to their financial problems. The liter of light is definitely innovative, extremely functional, affordable (if you get lucky you may be able to dumpster dive and not pay for a thing), and green. So if you’re thinking your garage is looking a little dark, then you might want to try out some liters of light out for yourself to see if they live up to the hype.

It’s rare that the simplicity of a project or initiative shocks me with its sublime form and function, yet this is one of those projects. I hope you enjoy “A liter of light” as much as I have, be sure to check out the videos below for additional information and demonstration.

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73 thoughts on “2 Liter Bottles of Light

    • You are right! The inventor is Brazilian and this is in São Paulo Brazil and the language they are speaking is Portuguese.

    • Nice Idea; but please tell me:How do you prevent leakings?
      Is it all about a plastic sealant?
      Silicone maybe or something more envirionmentally friendly?

  1. This is the most ingenious invention ever and surely needs great acclaim. I live in India where the villages have no electricity and the people have to rely upon kerosene lamps, many time staying in the dark because kerosene is usually in short supply. Hopefully some NGOs will latch on to this and make the life of the villagers less grim.

    • Yes, I agree with you here. Being able to limit the need of kerosene to nighttime or cloudiest of days would be a huge help to the economy in your area as well. I grew up on kerosene lamps, and they can be hard on your eyes. This liter of light idea must be easier to see by.

    • Denise, if you live in India, why wait for an NGO… Why not start this in your nearest village? Seems folks are always waiting for someone to start something, and seem slow to realize they are SOMEONE…

    • Yes, Denise… Don’t wait for anyone else… start this project yourself and you will see that people will jump at the chance to help you!! You could actually make a little business for yourself from it.

    • Wright home about the free light!! Make sure you tell them to put Clorox into the water( two cap fulls per bottle) to preserve the water.
      Also let them know that it only works in the day time so if the place is dark during the day this will work very well.

    • I was wondering about this too. You could seal around it with tar, but what is the price of a light bulb when you factor in the risk to your roof?

      • Yes, how can I cut a hole in my roof to try this out? Suppose it doesn’t work? I’ve ruined my roof, the shingles, etc. If it does work, how do I keep it from leaking?

        I’m having my doubts about this idea. I hope it’s true and a great help to those who can do it, but wonder if it’s not like so many other ideas that dazzle on paper, but are too difficult in reality.

        • You have to seal it in place with Silicone or some type of flexible sealant . The cheap cheap way is to seal it with Styrofoam and Gasoline , which you combine by putting icecube sized chunks of recycled styrofoam into a plastic 1 or 2 liter botttle 1/4 full of car gasoline . The foam is dissolved in the gas very fast and eventually makes a sticky gooey substance . Put a stick of wood in it and roll it around until you have a blob of it on the end and wipe it off around the joint of bottle light and roof . Look at YouTube videos of what they are doing in the Philippines . On an iron roof they usually mount the bottle on a separate piece of similar roofing and then mount that when they are on the job site .

          • That is NOT wise. styrofoam and gasoline combined produce a VERY flammable liquid called NAPALM. You know, the stuff they use to blow things up? Liquid refracting light can heat and on hot days potentially catch fire. DO NOT DO THIS!

          • I don’t think anyone in the slums has shingles they are afraid of wrecking – I saw the TV special on this and it’s a life saver for those living in slums – simple idea – simple solution – but oh such an impact – the guy who is installing these seals the hole very well and there is no leakage – and the only ingredients are really just a bottle, water and some bleach.

        • I think I may give this a try in my chicken coop to see how well it really works. If the sealant isn’t an issue there, I can see expanding it to other outbuildings I have. This is so simple, why hasn’t this become a common thing? Amazing, all this time, it’s right in front of us.

          • You are right! This IS amazing….we can light dark sheds, and out-buildings. I think it’s ingenious and I will pass it onto my physicist father who lives in a passive solar home…he will love it! I can’t do it to my home…like some of you said earlier…cutting through tile would be problematic….next house?

          • but something to think about is if the winter is cold enough to freeze wherever your using these .could cause some problems..

    • This would not hold light, just a little bit of heat from the sun. The idea is that the sun’s rays get absorbed into the bottle and then cast all around the room below the roof’s surface (look up refraction for a better understanding). So at night you would have to use another source of light. I do wonder if this could provide a new innovation in harvesting solar energy.

    • At night, it simply gets dark. For the place where this was developed, having ANY light without electricity is a vast improvement. The shacks don’t often don’t have windows, so the only way to get shelter is to be in the dark. This gets the residents light, at least during the day.

  2. More needs to be said about how it’s installed to prevent leaks. Also, given the shape of many bottles, what keeps it from falling to the floor? It’s a great idea for anyone who would otherwise need to use some other type of light during the day.

  3. Awesome idea! People living in warm countries can certainly benefit from something like that! It’s inexpensive and it’s probably better for the environment than electricity. Unfortunately it wouldn’t work here in Canada… the water would freeze and probably split the bottle or the seal around the roof.

    • In colder countries, a person could use a clear (grain?) alcohol. A bit more expensive than water, but if the light lasts for 5 years…

        • Kim was talking about colder climates where it was to cold to use water for fear of freezing. How would a climate such as that warm the alcohol?

          The alcohol would nto evaporate any more than the water would. With a cp on teh end this would be non existant.

    • If you don’t fill the bottle all the way, it shouldn’t split….same principle as leaving headroom when you freeze leftover soup. I freeze water bottles all the time to use in the cooler. Though I doubt you’d get five years with repeated freezing and thawing.

  4. Anyone try an led inside the bottle for night use? In the US, you can find these rechargable lawn lights cheap. The water would spread the light well.

    • I was thinking of it That, would need a different bottle to accommodate the solar light that could be screwed in the bottle mouth with some screws in the side.

      • Would you need a different bottle, or could it be attached to the bottom of the bottle somehow (maybe temporarily)? Maybe the light shining up instead of down would use the refraction of the water again in reverse direction reflecting off the ceiling? Then there would be light noise outside the house at night, though…

  5. I love this story – this is the second time I’ve found it around the web. Ingenuity at its best. Crazy to think what life was like before this idea. Let’s hope others catch on and take advantage as well.

  6. You will have to find someone to install it. It would have to be someone who knows about roofing. It would be great in a shed or something where leaking wouldn’t be a problem, but I’d be afraid to put one in my house unless it was professionally installed…like a skylight.

  7. Great Idea, and who cares if it leaks. If you live in a tin roofed shack with no windows, chances are the floor is dirt as well. Letting a bit of light in has to be a blessing when otherwise it’s lightless. Some of you commentors need to put yourself in the shoes of the people benefitting from this inexpensive means of lighting the interior.

    • I also don’t understand why people are being so negative. This isn’t meant as a solution for someone living in a US suburb. It would leak. My shingles would be ruined. I’d rather have a skylight professionally installed. You know what? When you have a piece of tin for a roof, I’m pretty sure you don’t have to worry about it being ruined by cutting a hole in it. When you can’t even afford to power one light bulb, you probably don’t have enough money for a skylight. I am also wondering if people even watched the first video where they show that sealant is used to, presumably, prevent leakage.

    • Who cares if it leaks?? Really?!? I can tell you as one who lives among people that could benefit from this…THEY care if it leaks! When it rains 5 – 6 months out of the year, you need a dry place to get out of the rain from. And yes the floor is dirt, which if it gets wet then becomes MUD. Most huts I have been in all have a built in ledge around the doors or are raised out a little hight than the surrounding ground to keep water out of their hut, off their bed and off their cloths and whatever else they might have. Otherwise they would not have built a hut or a house. So the questions of a sillimanite are VERY important to the lives of those I work with. I have seen. Store house for rice or peanuts sit empty or half empty due to leaks in the roof making the use of the building not an option as it will ruin their harvest. So again, the question of leakage and how to seal it up is very valid!

  8. How about adding a small LED in the top with a small solar panel and battery so it would light at night, like the Malibu lights in my yard? Might be hard to do in third world countries but here in the USA those things are fairly easy to come by. I will try one and get back with my findings.

    • The LED light you speak of is about equivalent to a 2 Watt incandescent bulb , where a coke bottle in the tropics is equivalent to a 50 Watt bulb.

    • Did you try this? I am wondering if you were able to use the 2W with the bottle to amplify the brightness of the light to 50?

  9. you know, some of you people are really morons. What makes it work??, what a dumbass question. I can see that this would be extremely beneficial in a poor developing nation. I hope that this reaches the people that need it most. Here in The USA, we take our power for granted. Untili a power outage. A few hours might feel like an adventure, but a lifetime, would be an eye opener.

  10. Oh Jesus H. Christ people, read the damn story before you broadcast your ignorance and rash stupidity, no wait, don’t just keep documenting that you are a fool.

    Holes in ceilings let in light sure….WOW…but you have no idea of how refraction works, you put a 3″ hole in your roof, you get a 3″ dot of light on the ground, but, as light travels through water it refracts…you’ve seen this if you’ve ever put a stick, your arm or something under clear water on a bright sunny day, it looks bent right at the surface??? DOH! THAT is refraction, and it transmits MUCH more light than cutting a hole in your roof, you dufus. Damn, the entitlement of some people….if you are looking at this on your nice imac laptop chances are you don’t live like the majority of people in this world, that is poor. I have many friends in impoverished nations, India, etc. This would work marvels, even on a cloudy or rainy day it would still put out much more light. I’m sure there’s a kit for it. If they can put a glass skylight in a roof, they can fit a 3″ bottle in one. Hole Saw. In many of the developing Nations, power isn’t something that is a given. Sometimes you’ve got the lights on, sometimes you don’t, and it just works like that. Let’s see what happens if we get a huge solar storm whacking the Northern parts of the US and Canada…we’ll see how long us “developed” people can get along without any power, especially if it fries the entire grid.

    All someone has to do is put this in a long lasting encased glass/or clear housing of polymer so it can be easily added to a new stick framed house in the first world. We can then have light from all over, it’s been done w/solar tubes, but this is so simple and smart.

    How does this work??? really? Little magic light fairies live in the bottles, they are very very tiny…so you can’t see them, but they have sparkly wands and that’s what makes the light sparkle. It even works at night.

  11. I like the idea and it would be great for when there’s just no more power. I’m sure the hole in the roof can be sealed to prevent leaking, but doesn’t this only work during the day? Is there something else you can put into the bottle to allow it to glow a few hours after the sun has set? Also, in colder climates, how would you keep the water from freezing. Light doesn’t refract so well in ice!

  12. It was created first in Brazil, 10 years ago… not by an engineer but a mechanic, someone from the poor people in need. They have lots of creativity!

  13. lmao, that nobody has figured out that putting them in the walls as windows would work just as well and you wouldnt have water dripping on your head.

  14. what about freezing and the heat that this would put off. if the bottles froze they would break and you would have to replace the. or could you solve that by not filling the all the way.
    how much heat will this produce in the summer. i would not mind the winter but our summers here are sometimes brutal.
    would like to try this in my shed where there are no lites. see how it goes.
    great idea though

  15. Thats good for slums……but guys….what about vertical light?….Glassed dome a bit of tarr…. and its done….no leaks….no problems.

  16. how are the “tops” of the lights made? and if they are specially made, could we use a substitute like electrical tape?

  17. Hey, I have a question. Would it stand to reason that this could also work in a sunny window? the bottles hanging in the window? We live in a hollow that is well protected but a bit dark sometimes, especially in the winter. But we do have some southern exposure windows with sun right on them for a good part of the day. Just wondering if there could be practicalities to this idea short of holes in the roof.

  18. It wouldnt take much for a roof-jack to be manufactured ( similar to those for pipe penetrations ) that could accomodate a plastic or acrylic bottle.

  19. This is an excellent idea! Really opens your mind to the possibilities. As far as freezing in colder climates…even using 50% water and 50% alcohol (really cheap vodka maybe?) should keep it from freezing and reduce any hazard of heated alcohol and evaporation. I would question how one would keep it in place? I suppose whatever you used (silicone sealant?) to keep it from leaking would anchor it? Definitely an idea worth experimenting with.

  20. please somebody could find out another chemical that could be added to the mixture so it can light up during the night too.. then I would consider that a real innovation else it’s useless.

  21. A fiber optic cable could be attached to the bottle and ran outside thru the wall to a side of a house with the most sunlight. It would allow the sunlight to travel down the optic cable to the bottle.
    It would increase the cost but would last pretty much forever with a simple replacement of the bottle from time to time.
    You could bundle a bunch of the fiber optic to a single hole in the wall ,then run each optic to a bottle in every room …pretty much the same way that electric wires are installed.
    As long as you had heat and the bottle was inside i don’t think freezing would be a worry in the winter.
    You could even rig a dimmer by restricting the amount of light the cable allowed into the bottle

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