En esta noticia
A simple plastic bottle filled with water can become an alternative for lighting dark areas of the home during the day, especially in homes that have few windows or limited natural light.
Known as the “Moser lamp”, the method consists of inserting part of the transparent container into the roof to take advantage of sunlight. The system, which was created in Brazil during a time of energy crisis, has over the years spread to more than 30 countries.
The origin of this trick: Why is this trick used in more than 30 countries?
The method is named after Alfredo Moser, a Brazilian mechanic from Uberaba who developed the idea in the early 2000s, in a context marked by problems in Brazil’s electricity supply.
His proposal consisted of piercing the roof with a transparent plastic bottle filled with water, leaving the top part exposed to the sun. In this way, it could take advantage of outdoor lighting to bring brightness to indoor spaces that remained dark during the day.
The initiative acquired an international dimension starting in 2011, when the organization MyShelter Foundation promoted the Liter of Light program in the Philippines, which adopted this system as an inexpensive and easy-to-replicate technology.
During its first 20 months, the project reached more than 150,000 homes in the Philippines and about 350,000 homes across 15 countries. Later, UNESCO references recorded the expansion of the initiative to more than 30 countries.
Its expansion is explained mainly by:
- The use of inexpensive and easy-to-obtain materials.
- The possibility of reusing plastic bottles.
- Its installation in homes with little natural light.
- The fact that it does not need electricity during the day.
- The possibility that communities themselves can learn to build and install the system.
What is it for to place a plastic bottle of water on the roof?
The bottle works as a kind of solar lamp for indoor spaces. When the sun’s rays reach the part of the container that protrudes from the roof, they pass through the plastic and the water.
The liquid allows light to refract and scatter in different directions, making the brightness spread throughout the room instead of concentrating only at one point.
For this reason, the method is especially useful in rooms with opaque roofs, few windows, or limited natural light.
How to do it correctly?
The principle of the system is simple: a transparent PET bottle filled with water is used and partially inserted through an opening made in the roof, leaving part of it outside to receive sunlight directly.
Some versions also include a small amount of bleach or chlorine in the water to delay the appearance of algae and keep the liquid transparent for longer.
It is not recommended to simply drill any roof and place a bottle.
For the system to be safe, one must:
- First, evaluate the material and structure of the roof.
- Make an opening according to the bottle’s diameter.
- Securely place the container, leaving part exposed to the outside.
- Seal and waterproof the entire perimeter properly.
- Check that there are no water leaks.
- Review the corresponding building regulations before modifying a roof.