Homemade Solar Air Heater! - The "Screen Absorber" Solar Air Heater!. Easy DIY. Produces temps near 140F (with outdoor air in the mid 40's). design of collector is similar to the steel can/aluminum can solar air heater but uses a "screen absorber plate" instead of the cans. video is a full tutorial with step by step instructions. how it works: outside air enters the collector at the bottom through several entrance vents. it then raises up through the collector (passing over, under and through the screen absorber plate along the way. when it reaches the top it's pulled out by a small fan through an exit vent. bottom piece of internal frame acts as a baffle which helps to spread out the airflow. short list of item sizes/dimensions: outer frame: One (1x4) cut down into Two 33 3/4" pieces and Two 20 1/4" pieces. inner frame: One (2x2) cut down into Two 26" pieces and Two 15" pieces. glass (plexi-Glas) used is 20" by 32" (always build your collector around the glass you have available). dimension of backing 33 3/4" by 21 3/4". hardware used: Twelve #8 3/4" wood screws for the backing. Eight #8 1 3/4" wood screws for the outer frame. Four #12 2 1/2" wood screws for the internal frame. vent tube is a 3" dryer hose (expands up to 8 feet). collector is painted with flat black paint. seal up the collector appropriately to match your local climate conditions (using weather stripping, caulk etc.). final thoughts... experiments suggest that a "dual layer" screen absorber plate works the best (single layer and triple layers of screen tend to produce slightly lower temps). *i recommend keeping the entrance vent "cutouts". those can be reinserted to adjust airflow (which could potentially raise/lower output temps - will do additional experiments). i experimented with putting the screen absorber at an angle inside collector but angling it did not produce higher temps. (*note that using no screen at all (just a black box) will significantly reduce output temps - they dropped down an average of 20-30F (couldn't get above 109.5F without the screen assembly)