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How to Build a Water Bottle Skylight

How to Build a Water Bottle Skylight


How to Build a Water Bottle Bulb

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I spend a lot of time looking at appropriate technologies coming from missionaries and other groups that work in third world countries.

I figure – if it works in areas lacking infrastructure then it will work if we ever lose our infrastructure.

This idea came from a couple of YouTube videos I saw of people making water bottle skylights out of 20oz soda bottles.

This is also called a solar bottle bulb.  Either way, the concept is pretty simple I have used this in domes and animal houses several times.

Most specifically I got it from the video at the bottom of this page.

I modified it slightly and was quite pleased that two of them gave enough light in my cement dome that I can see what I am doing.

Actually, if I am in the general area of one of the lights I can actually read by the light.

This technique was used on my Dome of Doom on Doomsday Preppers and it works very well.  I have a series on how I made my cement EMT dome.



  • 1 clear soda bottle
  • Water
  • Plastic roof flashing
  • 2 eyebolts
  • Wire
  • Duct tape
  • Mylar space blanket


  • Drill two small holes on opposite sides of the plastic flashing, and thread the eyebolts in the holes
  • Fill the bottle with water, leaving enough space that you can add about a ¼ cup of bleach to keep anything from growing in the water.
  • Cut the mylar blanket into a strip approximately 1/3 the height of the bottle.
  • Center the mylar strip in the middle of the bottle and wrap it tightly – you need to leave unwrapped bottle at the top of the bottle to gather light, and at the bottom to release it. – Basically you are making a reflective tube to channel the light.
  • Insert the bottle into the flashing, leaving about 1/3 of the bottle sticking outside the top of the flashing.
  • Wrap wire around one eye bolt, pull the wire tight over the bottom of the bottle, and then secure it to the other eye bolt – this keeps the bottle from dropping out of the flashing.
  • Insert the entire assembly on your roof and calk as needed to prevent leaks.


Over time UV light will degrade the plastic – but since soda bottles are everywhere, it is a simple process to rebuild as needed.


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