Social project uses pop bottles to provide indoor lighting for the poor


September 14, 2011

Illac Diaz (right) in a home equipped with one of his Solar Bottle Bulbs(Photo: Isang Litrong Liwanag)

Illac Diaz (right) in a home equipped with one of his Solar Bottle Bulbs
(Photo: Isang Litrong Liwanag)

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Perhaps you've performed that old camping trick before, where you created a lantern by shining a flashlight into a water-filled bottle. While that may have helped you find your marshmallows in the dark, imagine how much brighter that bottle would have been if it were lit directly by the Sun. Bright enough, it turns out, that it could brilliantly light up the interior of a one-room house. That's the idea behind the Isang Litrong Liwanag (A Liter of Light) project - it's bringing daytime indoor lighting to the homes of the poor in the Philippines, by installing water-filled plastic pop bottles through holes in their roofs.

Isang Litrong Liwanag is run by the Philippines' MyShelter Foundation, which was in turn established by social entrepreneur Illac Diaz. The group was founded to promote social enterprise, appropriate technology and alternative construction in the region.

The Solar Bottle Bulb, as it is called, was originally designed by students from the Massachusetts Institute of Technology (MIT). Its construction and installation is simple. A clear one-liter pop bottle is filled with water, chlorine is added, then the bottle is squeezed part way through a hole in a piece of corrugated tin. A corresponding hole is cut in the tin roof of a house, the tin-and-bottle is secured over the hole so that the bottom of the bottle hangs down through the ceiling/roof, then caulking is applied to prevent rain from getting in.

When sunlight hits the roof and the top of the bottle, its rays are carried down through the water and dispersed into the interior of the home, giving off about as much light as a 55-watt bulb. Given that many of these homes lack windows, they might otherwise be nearly pitch black inside.

Not only does the system produce light during daylight hours, but it is also providing a living for locals who build and install the Solar Bottle Bulbs, and it diverts bottles that might otherwise end up in a landfill. While the bottles don't provide light once the Sun sets, homeowners do at least have the option of performing indoor activities that require illumination during the day, when the light is available. They could also turn to solar-powered lamps such as the Solar Pebble.

Additionally, some homes do have limited electrical lighting, but the Solar Bottle Bulbs allow their owners to save electricity by not using that lighting before dark.

Illac Diaz has stated that he hopes to outfit one million homes with his system by 2012. We wish him luck in his endeavor.

The video below shows the installation process, and the effectiveness of the bulbs.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away. All articles by Ben Coxworth

Great idea!


Nice. If you use a 2 litre bottle does it equal a 100W bulb?

This could be useful even in the west. I\'m sure there are plenty of back yard tool sheds, fishing shacks and the like that could benefit from some extra light.



I'd make ONE upgrade - USE GLASS BOTTLES - they last an eternity, the plastic ones die in the strong UV.

Mr Stiffy

and use the rest off the roof for a garden!... I it can hold 2 men..

Jelmer ten Hoeve

A nice, cheap lighting solution. It could deliver even more light to lower areas of the room if lengths of 3 to 5 inch wide by X-inch long reflective metal (or any thin, long material covered with aluminum foil) were positioned on the ceiling forming a triangle, square or other geometric around the bottle at any desired diameter and down-facing angle to reflect more of the upper light (which really serves no purpose other than lighting the upper walls) down to where it is more useful.


I have seen log cabins with whiskey bottles fitted in between logs to provide indoor light. No water though, in Colorado it would freeze in winter.


This ideia is create in Brazil in 2008

look in :


Nice initiative . . . but IS IT ORIGINAL ? On July 2008, O Globo (one of Brazil\'s main journals) reported from Uberaba, Minais Gerais: \"Litros de Luz\" (liters of light) . . .,19125,VGC0-2703-17305-3-283127,00.html

E. M.

@Slowburn - doesn\'t whiskey have a lower freezing point? or maybe the light transmission is poor...

This is a lo-tech version of the Solatube lighting system and ideal for underdeveloped countries. One might ask why they don\'t have windows, or would that be spoiling the game?


This is brilliant. There used to be something on sailing ships that did a similar job - a deck prism made of glass, it had a flat area that was level with the ship\'s deck, and the prism shape shone the light through down into the holds etc.

Jane Lunsford

Re; agulesin

The miners, not being fools, drank the whiskey first.


Good innovation. But on usage there will be scratches. It is better to use a Glass bottle which reflects more light.

Dr.A.Jagadeesh Nellore(AP),India

Anumakonda Jagadeesh

Re;agulesin.. the reason they don\'t have windows is if you notice all these structures are against each other.


this really force me to say excellent this reallly made me impressed this is really a awesome post inside lighting thanks to post admin

Facebook User

Using glass bottles defeats the purpose of the design. The idea is to take a common waste product and use its physical properties (pliability, flexibility, lightweight, abundance....etc.) as an advantage. Glass is rigid, dense, heavy, and sharp-edged when broken. It has become a less common packaging material, and as a result, a more expensive material. The plastic bottle will require less sealing materials because of its pliability - insert empty plastic bottle into hole and then add water to expand bottle slightly, forming a basic if imperfect seal. Try THAT with glass.

Noel K Frothingham
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