** This is a very simple project, proving that you can have free heat for a few cents up front. A bit ‘of cardboard or styrofoam and some aluminum foil recorded with it. Putting in a window and get free solar heat. No moving parts and no maintenance. Take any type of rigid material and cut to fit perfectly in your window frame on the inside. Then cover with aluminum foil on one side. Cut a slit at the top and a slot on the bottom for air flow. Paint it all black on one side. Put the heater in a south window and now you have free heat when the sun shines. If you use polystyrene and completely cover the window, you also have a window insulated to reduce heat loss at home in the evening. Video Rating: 5 / 5
** This is a video showing the latest development in a window of bulk thermal plants. Designed to capture and store energy in only 3,000 pounds of water contained within this windowing system.