Solar Thermal air heater! Easy DIY. this vid. is an overview of my latest solar air heater. the design uses an "air channel" design to force the air to travel a route well over 12 feet inside of the collector. as the air rises it's heated to well over 150F. (tested w/outside temp in low 50's). no metal cans needed for this one (but optional aluminum flashing strips can be added to further increase temps). *or for the reuse/recycle option, try crushed aluminum cans along the channel. air is pulled out of collector by a small thin case fan ...and is run using a small solar panel (3 to 5 watt panel being the optimal size). the collectors surface area is roughly twice the size of any i've made so far (but it's super-slim design still keeps it lightweight). *the full video (posted 3 days prior) with full "detailed building instructions" can be found on my youtube channel video page. couple of things: i designed the collector to be able to pull air from outside or inside. to pull air from inside home just hook up a second vent pipe onto the air inlet at the bottom and feed both tubes in. also note; due to the collectors slim design i used a very thin case fan to allow for proper airflow. (if you want to use a standard 25mm style case fan, consider using 2x3 or 2x4 lumber for max. airflow (and adjust the internal dowel sizes accordingly).