Topic done to death before,two new ones this week alone. And thus my post gleaned from archive For any climate colder than San Francisco this is a very bad idea in a heated space. Liquid filled bottle will be a huge thermal wick and rob you of far more
energy than it supplies. Use these bottles on your shed but not in a heated building. Almost any window idea you can come up with will be better than this one. You'll notice none of the roofs in the videos were insulated. This isn't because insulation is unnecessary, it simply a function of poverty and lack of resources. A roof like that gets hot as hell here in Canada so it must be even worse in tropical heat and humidity.
