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TheNickboy writes – “Summer is nearing/here, and it’s getting hotter in my house. To save electricity with our super expensive A/C, I constructed reflective curtains to block sunlight from warming our house. Think auto windshield. This is super simple and kind of obvious, but it works well.”Link.

Phillip Torrone

Editor at large – Make magazine. Creative director – Adafruit Industries, contributing editor – Popular Science. Previously: Founded – Hack-a-Day, how-to editor – Engadget, Director of product development – Fallon Worldwide, Technology Director – Braincraft.



  1. wholepair says:


    I made some curtains recently too. I put them in there very own Flickr set.
    Check them out -> Computer Card Window Shades

  2. fxer says:

    Will these curtains work inside the window? Once the sunlight comes through the glass, hits the curtain and turns into IR, it won’t go back through the glass readily will it?

  3. Unomi says:


    I thought that as well. For years now, we do the following:
    During the night and morning we open all things not facing the sun. So cool air flows in and moist can get out. After some hours in the morning everything gets closed and the side(s) facing the sun get covered like above, but on the outside (if possible that is). That way minimal heat is getting trough the window and open spots.

    It works when not having A/C available. When opening doors or windows for airflow, try always the shadowy side not facing the sun. Because the air outside is heated by radiation from the sun too. Shadowy sides are less warm.

    - Unomi -

  4. tms10000 says:

    “Once the sunlight comes through the glass, hits the curtain and turns into IR, it won’t go back through the glass readily will it?”

    Once the light comes in through the glass and hit any dull objects, like the carpet (especially carpet), wood floor, furniture, anything, the object heats up and radiates IR.

    Glass is good at not letting that go out (so are your walls) and it is a good thing when you actually want to keep the heat inside.

    If you line up the windows with a reflective (the most reflective, the better) the light (well, some of it) will be reflected *as light* through the window, back outside.

    Aluminum foil here is particularily well suited, because it is cheap, thin, and highly reflective.

    The more you reflect the light back out, the less is absorbed and radiated as IR inside.

  5. tms10000 says:

    And for the heat, you can also rig a fan with some copper tubing, an ice/water tank and an aquarium pump. I’ve seen these projects here and there.

    Also, a fan will use about 10% of the electricity needed for AC. Then again, a fan only moves air. Only works well when it’s blowing on you and you are sweating.

  6. Good idea – like you said, simple and obvious, yet I had never thought of it! The silver lining isn’t exactly to my taste interior design wise, but as a solution to a heat problem, this is great.