How to Build a Solar Space Heater How to Build a Solar Space Heater
You can easily heat a garage, shed, or even your entire home for free, after a small investment, if you build a solar space heater. For just $350 and a little elbow grease, you can convert any South facing wall in your home into a Solar Space Heater. The term space heater may give the impression that it is a small, portable device. However, a solar space heater must have a large collector in order to produce enough heat to keep your area warm. By following these directions, you can create a permanent heat source for your area that will pay for itself in the first year of use.
Step 1- Determine the Area for the Solar Collector
The first and most important thing is that your home has a wall facing South with a clear view of the sky. To get the most out of your collector the area should not be obstructed by trees, fencing, or a neighboring home. The amount of heat you can produce is directly determined by how much sun your collector receives, if it does not get sun all day, it's usefulness will be depleted. Even if you South wall has windows, you can alternate panels on either side of the windows and still get the same effect. These instructions will mainly focus on a solar collector built in one piece, but since it consists of panels, you can separate them. Equally important is making sure that your building has adequate insulation, if your home or area is drafty the solar space heater will have a hard time keeping it consistently warm.
Step 2- Outline Your Construction
Examine the wall that you will build your collector on. The size of the collector is 8 feet high by 20 feet wide, and is made up of 5 connected, 4 feet wide panels. You can make yours larger or smaller, just adjust the amount of materials needed accordingly. You will need 6 vertical supports that are 8 feet high, each of these needs to be offset from the studs of the home so that they can be lag screwed from the inside of your home. Use the 2-by-6 inch wood for the vertical supports and cut 6 vertical pieces each of them 8 feet long, using a table or hand saw. Locate the studs to determine where to offset these vertical pieces. If you feel that your siding will not be able to hold the weight of the collector, you do have the option to mount the verticals against the studs and drive lag screws through the verticals and into the studs from the outside. If you decide to go this route, adjust your vent spacing accordingly. You will need to cut between 4 to 10 circular or horizontal vents, as long as there are vents for at least 50 percent of the width of the collector. Mark the vent locations on both the inside and outside of the building to make sure you won't have any electrical wiring conflicts. Now that you have everything marked and outlined, use a reciprocating saw to cut the holes for the vents. Use the appropriate blade for your building's structure.
Step 3- Building Your Solar Collector Frame
You already have the 6 vertical supports cut, now cut the top sill out of the 2-by-8 inch wood and overlap the end vertical pieces by at least an inch. Using your table saw, bevel the back edge of the top sill so that it slopes about 10 degrees when placed against the siding. This will help shed rain. Next, angle the tops of the verticals so that they match the slope of the top sill. Then line everything up and cut notches into the vertical supports for the 1-by-1 inch horizontal supports. You will use the remaining 20 feet of the 2-by-6 inch wood for the bottom sill. Now that everything is cut, prime and paint all of the pieces. You can paint the collector to match your siding, or any other color you choose. Painting the siding behind the collector a dark color will improve efficiency slightly, but it is not necessary. As soon as the paint has cured, mount the verticals to the siding using the lag screws. Use at least 4 lag screws per vertical, or less depending on the size of your collector. As mentioned in Step 2, you can choose to mount them offset by driving lag screws with washers from the inside of your building, or use lag screws to mount the verticals to the studs from the outside. Pay special attention to keep everything level, because the polycarbonate sheets will only fit properly if everything is straight. Now attach the top and bottom sills. Seal the entire perimeter of the collector with Silicone Caulk.
Step 3- Constructing the Collector Panels
Cut the window screen into 5 different 4 feet sections. Mount the battens and staple the sections of window screen across each panel. You may need to fold over the edges of the screen to fit inside each panel. Now make your 4-by-8 foot glazing panels. Overlap them by one corrugation and apply a light bead of silicone caulk between the layers. Secure the joint by fastening an 8 foot strip of the 1-by-1 inch wood on the inside of the overlapped corrugations using screws with washers made from EPDM (a synthetic rubber that stands up to sunlight and varying temperatures). Then install the horizontal 1-by-1-inch support strips into the notches made earlier on the collector frame. The surface of the strips should be flush with the frame surface.
Step 4- Mount the Glazing Panels
Install foam molding strips, which are molded to fit the corrugated panel's contours on the top and bottom sill. Run caulk along the first set of verticals and mount the first glazing panels. If you have trouble getting it to fit, your frame is not straight, you need to fix that before proceeding any further. If it does fit, fasten the panels to the frame using screws and the EPDM washers. Install the remaining sections, overlapping each by one corrugation with a line of caulk in the overlap. Finally, your collector is finished.
Step 5- Install Vent Flaps
You will want to install flaps on the vents so that you do not lose the warm air as the night air outside begins to cool. First attach half inch hardware cloth mesh over the vent holes to prevent the flap from getting sucked into the hole, then you can simply use a cutout layer of a garbage bag as a vent flap. During the summer you can use cardboard to cover the vent holes to make sure you don't lose the cool air inside the building.
That's it! You will spend an average of $350 on these materials and your cost will be recouped within the first year of using your new Solar Space Heater.