glass, plexiglass, or some kind of clear material.
black aluminum window screen
caulking, paint, screws, lag screws, staple gun + other tools
I have some results on temperature differences from the first weeks of operation. Just like when you put up your first wind generator, the wind won't blow for days/weeks, I had overcast and mostly cloudy weather the first few days operating this thing. The heater puts out 87 to 104 degrees F at the vents on partly cloudy days to sunny days. The uninsulated garage hits about 17 to 30 degrees F above outside temps, very comfortable for me. It seems the colder it is outside, the bigger the temperature difference between the garage and outside. If you want more heat in an uninsulated area I would recommend possibly 1/3 more collector area than the ratio I give in the instructions. Seal up any drafts, it will do a lot to hold the heat. This thing works great.
Step 1: Frame and Fit
I sized the solar collector based on the numbers from the Mother Earth article where the guy built 160sq ft. of collector for his 700 sq ft building; using that ratio I built a 48 sq ft collector for my 200 sq ft garage.
Step 2: Paint and Add Screen Mounting Boards
I notched the middle board for a 2x2 that will later support the glazing.
Step 3: Mount to Wall and Seal
Seal the box from the inside with window and door foam. Also seal the bottom 2x4 that holds the screen.
Step 4: Cut Vents into Wall
My vents are 4" x 16"
The cuts are not pretty, use foil tape to trim the inside edge of the vents
This was the toughest part because I didn't have a good saw.
Step 5: Install Metal Window Screen
Note, this needs to be metal window screen for good heat exchanging; fiberglass screen won't work well.
I used 48" wide screen and had to trim the edge some with a utility knife.
Step 6: Install Glazing and Vent Valves
On the top vents in the building you'll need to put a flapper valve made from plastic sheeting or a trash bag, this keeps the warm air from leaving at night as the heater would work in reverse. Also put some screen on the vents to keep most of the critters out and to keep the plastic valves from sucking into the vent.
Using recycled wood and some on-hand hardware, I spent around $100 for this; now I'm enjoying free heat.
Ducting with a fan and a thermostat switch is what they use on commercial versions installed on homes. That works well for precise heat control. I like convection, no moving parts; and I will just close the vents when the weather gets warmer with some cardboard stapled to the wall.