Interesting: aluminum can solar heater

[White Tiger]

This probably won't help anyone living in an area below 30 degrees...but it does offer some interesting and cheap/free options to improve heating (somewhat) in any condition.

http://www.permies.com/t/6580/solar/Aluminum-pop-beer-solar-heater

Here's another site with someone who employed this "technology" - with a better step-by-step format.

http://solar.freeonplate.com/diy-how-to/DIY-solar-panels.htm