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Reflective Windows

Emily found a simple and cost-effective route to a cooler apartment – prevent it from heating up in the first place.

Using inexpensive and easily found materials — foamboard, aluminum foil, tape and glue — I made insulating panels for my windows that reflect the summer sun away from my apartment, cooling down a room without using a lick of electricity. My bathroom temperature went down 10 deg. F or more with these. Here are my DIY instructions on how to make them.

Beat the Heat for Cheap

Related:
Heatblocking Curtains
DIY Heat blocking curtains


  • Varnster

    i feel sorry for the people who live opposite or are passing by on a sunny day, as they may be almost blinded by the bright reflection. Just a thought…

  • Collin Cunningham

    @Varnster – I hear what you’re saying. From my experience tactics like these do only become necessary on higher floors, likely outside passerby’s immediate vision

  • Jordan

    It’s forbidden by my lease to use aluminum foil as a window covering.

  • Dodge

    Good luck when the window frame heats up.

    This is why people have drapes.

  • Gabe

    While this works great for insulation, the outside world will think you’re growing bud. That’s why it’s forbidden on a lot of leases.

  • Jim

    I find it hard to believe 1) someone did this and then bragged about it 2) someone else read it and thought the idea was good enough to share.

    Let me offer a less tacky solution:
    Lowes and Home Depot sell vinyl pull-down shades that they will cut to fit your window. They offer the same light-blocking benefits as foil, are more durable, and look much nicer from the inside and outside.

    And they are very inexpensive (~$10), and they are much easier to install than the solution presented here. (two screws to hold the mounting brackets, and you’re done.)

    I’ve used them to blackout the windows in my converted home theater room.

  • Ben

    Reflectivity:

    Aluminium foil: 70-75%
    Semi-Gloss White Paint: 75-80%
    Flat White Paint: 85-93%
    Mylar: 90-95%
    Foylon: 94-95% (the second photo used this)

    Basically, the only thing aluminium foil has going for it is that it’s cheap, but, really, so is white paint, and it’s more reflective.

    Honestly, I’m going to have to go with Jim’s suggestion: here’s a thought for a window: Blinds. Forget the vinyl crap, though; they are not opaque to light. Get metal blinds.

  • Collin Cunningham

    @Jim – believe it!

    @Ben – smoothed foil would have more directional[less diffuse] reflectivity than flat white paint – this might be to some advantage if nearby architecture/window frame/etc must to be avoided.

    huh, didn’t expect this discussion to get so . . . heated.

  • Jim
  • Anonymous

    Aluminized Mylar emergency blankets work wonderfully as reflectors (since that’s what they’re supposed to do anyway). If the lease/local zoning prohibit “foil” in the windows directly, you can laminate it to the back of cloth with some contact cement.

  • Anonymous

    At work we have the emergency blankets on the windows as we are not air conditioned. they’re working remarkably well and I just put some up at home and also notice the coolness there. They’re only like a buck each and they work, so what’s the big hub bub, eh?

  • James

    A Much better solution can be found if you use exterior shade screens. My wife and I installed a new do-it-yourselfer product called EZ Snap Exterior shades. See their website at http://www.ezsnapdirect.com . This product made an hugh differance in the heat build up in our house. It was super easy to install and the best part was that you can see right through the shades as if they were not even there.

  • http://www.plasticblinds.net Plastic Blinds

    This is cool! And so interested! Are u have more posts like this? Plese tell me, thanks