Preparation

• Air heaters lean against the window frame from the lower edge to the ground, at about a 30-degree angle. The window is partially open, just enough to make a seal around the matching measured panel. The amount to open the window depends on the height of the panel, but the width is fixed at the sides. Measure three sections of 2- by 4-inch lumber and mount them to a section of plywood to make an open-ended box; the plywood section should be a rectangle the width of the window by the length of the window frame, to the ground at the 30-degree angle. The 2-by-4s are mounted on edge, to give the panel the maximum depth. Other sizes of lumber can be used for a taller opening, but limit it to around 12 inches. The lumber is held to the plywood with wood screws turned clockwise.
  
  

Creating Air Flow

• In the panel mount four small squares (4-inch cuts) of 2- by 4-inch lumber, one for each corner. They should lay flat, and be half as high as the panel "wall." They can be held in with wood glue or screws. Measure and cut another section of plywood slightly smaller than the panel, so that it fits into the panel and can lay on the 2- by 4-inch squares. It should also have a gap at the bottom of about 3 inches, to allow circulation. Once this plywood is secured with screws, it should be painted flat black and allowed to dry. The black paint is crucial, is it absorbs the maximum amount of sunlight striking the panel and makes the air warmer. Once the paint is dry, secure a section of Plexiglas to the top of the panel, sealing in the black section. A good caulk or heat-resistant adhesive works well for this.
  
  

Mounting

• The panel will get the maximum effect and air flow with direct sunlight, so start with the best possible window. Lean the panel against the window frame and secure the bottom of the frame to the plywood with wood screws and brackets. There will be a gap between the top of the panel and the window, this can be filled in with measured sections of plywood or simple cardboard, depending on the situation. The wood can be sealed with tape or caulk, but the more permanent the installation the harder it will be to remove come summertime. From inside the room, the panel will be seen as a sandwiched plywood box, with a top and bottom gap. Using cardboard, create ducting to make a divider that directs the air to the desired location in the room. The bottom gap draw cool air into the panel by the vacuum of the warm air rising out of the it, to be deposited back into the room via the top opening. For the maximum effect, place venting for the bottom opening on the floor, but leave the top vent stationary.