The purpose of this solar heater is to concentrate heat from the sun on a black surface and radiate it into the room. It fits around/onto a window and can serve as an indirect fix for poorly-insulated windows. Ideally, the window will be south-facing in order to catch the most amount of winter sun. This project is designed for a 6x2 foot window, but measurements can be adjusted accordingly.
Two six-foot 2x4’s
One sheet of ¼ inch plywood (in our case it was 44x72 inches)
2 yards of black felt, 2 feet across (or fit to window)
Wooden molding (½ in.)
Step 1: Making the Frame
In our case, the window was 6x2ft.
Cut a 2ft. portion from one of the 2x4’s for the base of the heater
Cut 4 inches from the other 2x4 then cut in half (keeping in mind that 2 inches on each side of the frame will be comprised of the 2x4 laying across the bottom of the frame)
Step 2: Adding Plywood to the Frame
Measure and mark plywood then cut to make into a 6x2ft. sheet
Nail the 2ft. 2x4 into ¾ of a rectangle at the top of the two 68in. 2x4’s at right angles.
Place glue around the frame on one side and nail the 72x20in. plywood onto the 6x2ft. frame.
Step 3: Add the Felt
Now place the felt into the frame, keeping it flush with all of the edges. Then nail the wooden molding along the length of the inside of the frame.
Next, use the drill to drill holes through the felt and plywood. Any size and number is acceptable, keeping in mind that this is to allow air to circulate upward against the black felt
Use scissors to clean up edges around the holes to allow optimal air circulation.
Step 4: Installation
The heater requires little to no effort to install. Simple prop it up against the window if it is ground level, or balance against window using a surface to raise the elevation of the heater so that it covers the window. It is most effective if used with a fan to evenly disperse the hot air throughout the room, otherwise it may concentrate above, close to the ceiling.