If you're looking for a green way to heat up a small indoor space, Seattle resident Peter Rowan shows you how to make a solar powered heater using a bunch of leftover soda cans.
The panel is filled with cans painted black to soak up heat from the sun and get hot. Then cool air travels in one end, heats up as it passes through the cans, and then hot air comes out the other end. Air can be moved through with or without fans, but if you choose to use them, using some solar power is a smart way to go. The project is pretty extensive, and you need a total 240 aluminum cans. So it's not something you could go out and build today, but the end result is an effective alternative heating method. For a complete guide check out the link below.
Update: Looks like we've featured a similar heating solution before. Sorry for the repost.
Building a solar heater with recycled cans | *faircompanies via Adafruit