Although summer is just starting, I'm thinking ahead to next winter. I live in what the British call a "garden flat" - the street is at about my waist level when standing in my Cleveland Heights apartment - and I have a large window on the south that gathers a lot of sun, but I also have several smaller windows on the west side, in the shade of another four-story building a few yards to the west. I have been thinking about building some solar collectors, probably just out of plywood, aluminum foil and maybe a piece of plexiglass on top to keep the rain off, to funnel sunlight into my apartment during sunny but cold January days. Will this likely make enough difference in saved heating fuel to be worth the trouble?