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How about a FREE easy to build solar heater, from TRASH! (Read 3861 times)
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How about a FREE easy to build solar heater, from TRASH!
Feb 14th, 2011 at 11:34am
Take a old cardboard box that's bigger than your window, bend or cut sides out so it fits inside the window recess snug. Maybe 2 or 3 inches deep.

Use package tape around the box to make it's as air tight as it can be. It should be snug up against the window and/or the window recess.

Take either black construction paper -or- black trash bags and line the box, staple or glue it to the inside cardboard. Do not use paint! Paint smells and who knows what you are breathing.

Make a hole in the bottom / back for a old power supply fan to blow into. Make a hole at the top for output. If you can, make it diagonal from the other hole so air covers the whole box.

Power the fan from small AC supply ( 8 W ) or a solar panel.

A solar panel can be mounted so that it's right up against the window, and still inside the box. It will get hot and generate heat almost as good as the black surface anyway.


For a 3 X 3 ft window you should get the equivalent of a 800W space heater for as long as the sun shines on it.

Optional: One way flapper valve. You can make your own out of cardboard, use package tape as your hinge, or buy one made for clothes dryer tubes (check hardware store), put it right at the fan output. Keeps out cold air at night but restricts flow a little.

You could also insulate the back side with styrofoam or aluminum foil for the night cold.

Summer comes around, remove box.

If trash bags start to crumble after a year (bio degrading), replace them, it's cheap.

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