Adapting a Car Sun Shade for a Home Window

South-facing windows are great during the winter, but can be unbearable during a summer heat wave. Closing the blinds or curtains helps, but the heat (infrared) still passes through the window which is why the blinds feel warm to the touch. Window films are better at blocking or reflecting the rays, but they can obscure the view at other times of the day and may need to be removed during the winter.

This Instructable shows you how to repurpose a car sun shade for an "as needed" window heat shield, even for windows that open vertically.

1. Car Sun Shade (Fan-Folding style is better). Larger ones are approximately 60 inches x 30 inches (150cm x 75cm).

2. Clips (i.e., Binder clips, Chip clips, or even Magnets) - Optional depending on window and sun shade

3. Support Rods (i.e., Yardsticks, Garden Stakes) - For vertical windows

If you're lucky, all you need to do is place the sun shade in your window and close the blinds. For ventilation, you can open the window slightly and fold back the sun shade as needed.

CAUTION: It is recommended that you install the sun shade FLAT. This not only prevents the sun's rays from getting past the window, but more importantly, fanfolding may tend to concentrate the reflected rays and create a solar cooker effect (not desirable unless you plan to simultaneously cook some hotdogs)!

For vertical windows you'll need support rods and clips. As noted earlier, install the sun shade flat. For ventilation, you can open the window slightly and fold up the sun shade as needed.

Self-expanding sun shades can also be used, but the one-piece style tends to limit adjustability. With a two-piece style, hold the halves in place with clips or even magnets.

For me, this window faces the backyard so I can leave the sun shade in place without being an eyesore to the neighbors. In late evening I fold back the sun shade and use the window fan for extra ventilation. This arrangement keeps the room bearable during summer heat waves.