The first thing you need to do is prepare the window in which you plan to install your solar heater. Ideally, you’ll want a south or west facing window that gets plenty of sunlight throughout the day.
In addition, it’s nice if this is a Low-E window with strong insulation values. Otherwise your heater will continue to heat your home with the window closed on warm days. If you decide to use this on a drafty old window, you’ll probably want to design it to be easily removable for the summer months.
Most homeowners will try to strike a balance between a window with great sun exposure and one that’s not clearly visible from the street for aesthetic reasons.
Take careful measurements. Remove the screen from the window that you plan to use. If you fail to do this, the screen will melt from the heat. That’s right; you’ll be able to generate enough heat to actually melt a screen.