Select a west-facing window and measure the height and width of the inside frame. Measure the height of the glass bottles that will make the water wall. Calculate how many rows of glass bottles will stack up to fill the window.
Cut three-quarter-inch boards in lengths to fit the inside width of the window. The boards should be about as wide as the window recess is deep. Cut one less board than the number of rows of bottles for the window. You will need two boards for three rows of bottles or glass jars, three boards for four rows. Take measurements to the hardware store or lumber yard if you are having the boards cut there.
Screw right angle braces to the four corners of the underside of each board. Line up the unattached side of each angle brace so it is even with the outer edge of the end of the board. Use the height of the glass bottles to calculate where to fasten the first shelf to the window frame.
Position the shelf in the window recess and place a carpenter's level on the board to be sure it is even. Then mark the holes in the braces with pencil on the side of the window frame.
Set the shelf aside and drill holes for the screws in a stucco or plaster window frame or use a hammer and nail in a wood frame to start a hole in each of the marks. Replace the shelf and screw the braces to the window frame.
Repeat this process for as many shelves as you are installing. Fill the glass bottles with water, put lids on them and place rows of bottles in the window. The water will refract light around the room and block heat during sunny hours, releasing some heat after the light fades for the day.