Updated on 08.26.14

Innovative Energy Saving

Trent Hamm

Using a Solar Blanket, Hair Clips, and Curtain Rods

Only very rarely do I pass along a guest post, but a reader sent me such a spectacular energy saving do-it-yourself idea (and wonderful writeup about it) that I just had to pass it along. The only change I’ve made to this article is highlighting a few key pieces. This article comes from Allie, a long time reader of The Simple Dollar who likes frugal hacks at least as much as I do.

I don’t post much but I really wanted to share this energy hack with you. I think it would be a help to many readers.

I live in Central Florida. Our very old farmhouse faces west, and there’s no longer any trees to shade it. So on any given day from March to September, during the afternoon, the west side of the house (where the ancient windows are) is HOT. Hot as in you can barely touch the glass. I don’t want to use the “fry an egg” cliche but my mom thaws food on the windowsill in record time. A credit card placed there will be floppy in a couple of hours.

The a/c (necessary for me, an asthmatic, and my elderly mom, to breath in wet-wool-blanket heat) pounds away, sucking money out of my pockets to where I can almost see it flying.

I investigated solar curtains, solar shades, and they all were priced out of my reach. However, after studying them for a while, I came up with this hack:

For every window, buy an emergency solar blanket, sold at Walmart and other stores for about $1.99. They come in a box the size of a deck of cards in the camping section. Buy a couple extra for emergencies: they make a great emergency poncho, tent or clean place to lay an injured person. They vary in size, but are about the size of a twin sheet. They are thin and tough, like tissue foil. Gather up some tension curtain rods (I got mine at yard sales but the Dollar Stores carry them and you can buy the small diameter, the foil material weighs nothing) to fit your windows, and some of those inexpensive jaw clips women wear in their hair. Any family with females will have an abundance of these.

Fit the tension rod inside the window.

Lay the blanket, which comes compactly folded, over the rod, and unfold until it is the right width to completely cover the glass. I even up the front and back ends for double insulation

Secure with the clips over the rod – two does it for a 36 inch window. Tweak it until it covers all the glass – I use a bit of tape or small thumbtacks to anchor it.

Re-arrange your normal window covering over it. You’re done.

The house will be somewhat darker (although if you use just one layer, it is like window tinting and does let some light through) and the temperature will drop. In my case, I was able to raise the a/c to 76 and maintain an ambient temperature of 73 in the house, which is poorly insulated due to its age, during 90 degree days at 1700-1800 hours, the time when the sun is fiercest. The west side of the house was maybe 75 in front of the large windows and with numerous ceiling and floor fans, quiet pleasant. If you put your hand between the foil and the window, you can feel the intense heat that’s being blocked. The foil remains fairly cool.

Trent, I did 6 36-in square windows for less than $20.00 total. It might have been a little more if I had had to buy the rods new. Time – less than an hour. But that’s still a bargain. I also stapled neatly cut sheets over our glass window insets… anywhere that afternoon sun blazed in.

Our bill (scandalously high) showed a $75 reduction during this record heat and best, you no longer feel that you are walking by the Gates of Mordor when you pass a west-facing window.

In the winter, they are quickly removed and put away – I’ve folded them and used them over and over. I’m not going to say they add a lot of curb appeal, but function bests form here. People in well-insulated houses may be able to get away with a single panel, thus saving more money on the purchase of the blankets.

I have plans to insulate, of course, replace awnings, plant trees, but survival is taking priority. I will say that we do utilize this intense heat in green ways: the Magic Windowsill Thawer, the world’s fastest and best sun tea, clothes that dry almost instantly on the line, and even with conventional plumbing I can take a warm shower using the cold water tap if I’m fast. The resources are all around us, we just need the tools and thoughts to use them. I look forward to the day when my heat pump and solar panels are installed and the power barons buy energy back from me – that’s my goal.

Anyway, Trent, if you can present this idea – I didn’t intend an article, I just wanted to pass the idea on – I truly think it would benefit our frugal friends. Sometimes when something works, you just want to share it. Feel free to use this idea as you like. My small gift to you after so many large gifts given to me here at The Simple Dollar.

A final note: What’s happening here is that the blankets essentially reflect the light that comes into your home. This will work spectacularly well for unused rooms. The best part is that it’s incredibly easy to put up and take down as you wish (even if you just want to use it during some summer daytime hours, for example).

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  1. Des says:

    If you’re not going for aesthetics, why not just tape up some aluminum foil? Does the material in the solar blankets do something special to keep heat out?

  2. Vicky says:

    I’ll note you can also accomplish this with tin foil, however you neighbors might complain about you blinding them. :) Oh, and apartments usually won’t allow this.

    My mother has always just hung several very, very heavy, thick blankets (comforters even) over windows to block out light. I have bought the supposed light-blocking UV curtains for $20 a panel to give those a go – they DO work but at a pretty penny… (I only bought one, to try)

    I also live in Central Florida so I feel the pain of that awful, awful heat – but I’m fortunate to have trees saving me the brunt of it! I have since made very thick, very heavy curtains to cover most of my windows (and they’re pretty!) out of sheets and other materials I find at various yard sales or Goodwill for fairly cheap that is also very helpful. It won’t reflect the sun out and blind you, but it will keep it from coming in.

  3. Brendan says:

    I forget where I saw this, but it’s supposed to be even more effective if you hang the window covering *outside* the window. Then the sun’s rays aren’t penetrating the glass and heating the air between the blanket and the window. While it may seem like a small amount, it adds up over time.

  4. Maureen says:

    I’ve used aluminum foil in windows in my apartment without problems. I’m fortunate that my current home has a mature maple tree on the south side of the house.

  5. Johanna says:

    What a great idea. To make it look a little nicer, you could buy a pack of clip-on cafe curtain rings for a few dollars and use them to hang the blanket from the curtain rod instead of draping it over the top. (They’re also good if you want to make your own curtains out of cheap bedsheets or any other piece of material, since you don’t need to put any holes or loops at the top.)

    In fact, I suspect that it would work just as well if you folded a thin, light-colored bedsheet around the outside of the blanket. (Lay the blanket on top of the sheet, fold in half with the blanket on the inside, and then attach the clip-on rings to the fold.) Then the neighbors wouldn’t see the foil from the outside.

  6. Scott says:

    If you want a temporary solution (let light in sometimes or half window, etc). Take the same foil blankets and some spray glue and bind to the back side of a spring loaded shade and then you can raise and lower at will. As thin as the blankets are, it should work perfectly. I have not tried this myself but it seems workable.

  7. Gretchen says:

    hmmmm. Good idea.

    Does the energy savings come mostly from the blocking or from the reflection?

  8. Jackie says:

    Savings would be better if placed on the outside of the windows, although this is often not practical, especially in windy areas.

    Tin foil would work same as the blanket, but is more prone to ripping and tearing with handling.

    Most of the savings is from blocking, some from reflection. The area between the window and the blanket will be very hot, backing it with your regular window covering provides an additional layer to avoid convection into the room.

  9. Jennifer says:

    This is very interesting. I always carry those emergency blankets with me when I’m backpacking in cool temps. I thought the idea was that they would ABSORB heat, not reflect it!

  10. Cheryl says:

    For our home in Arizona, we bought foil insulation at Home Depot. It’s like those things people use on their car windshields. Comes in various sized rolls. We measured the windows and cut it to fit, but just a bit larger so we can wedge it in. No need for rods with this method. In our RV, we do something similar. The pull down shades hold it in place.

  11. Foo Finance says:

    Would this not work in reverse in the winter too? Keeping the heat in?

    Some will say the sun provides heat during the day but insulation works both ways. It keeps in cool AND heat.

    So my theory is that by doing this year-round you keep the heat in at night since winter has shorter days anyway.

    Am I wrong here?

  12. chacha1 says:

    Excellent ideas!

    I like Allie’s solar blanket suggestion, and think it will help a lot in our big west-facing apartment window – we already have double curtains, but with no view, and no immediate neighbors, there is no reason not to add a reflective layer!

  13. Brad Fletchall says:

    It’s not the visible light that is being reflected the lowers the heat it’s the UV rays and radiant heat from the sun. For a bit more money you can get a permanent solution that is basically the same tint that is in your car except it is perfectly clear but blocks UV. Since it actually sticks to the glass it is even more effective. The small gap between the window and the blanket or foil still lets some UV in. This site makes a DIY version http://www.snaptint.com/product.php?productid=16192

  14. wren says:

    One question: will the intense heat that builds up between the window and the blanket damage dual-pane windows (i.e. damage the seal0? The house I rent has dual pane windows, but I don’t think they are fitted very well, and the desert sun in the afternoon is fierce. Even thought the thermal windows here aren’t great, I don’t want to bust the seal and end up having to pay for replacing them.

  15. zach says:

    Thank you for the suggestion! My second floor, south-facing, poorly insulated, vintage apartment in LA gets so hot in the summer, I will do about ANYTHING to feel more comfy inside, even if it is darker. I installed heat reflective window adhesive, but I think this idea will work better.


  16. Leah says:

    I’ve heard of something like this before, except you use plywood sheets covered in this stuff. One side of the plywood has dark fabric and one side as light (or silver foil). That way, you can reflect light in the summer and absorb it in the winter.

  17. jesinalbuquerque says:

    This is a good idea. Even simpler, I have a big west-facing window and I picked up one of those foil windshield shades (big size) and just stuck it in the window. When it cools off, I can just fold it up and shove it behind something.

  18. Michele says:

    Great post!
    I actually already have some tension shower rods since I used them in our killer sun windows for plant starts in the spring with some shop lights- now all I need are the solar blankets! Thanks so much for another great suggestion!

  19. Maya says:

    My husband and I hang canvas awnings from the eaves on the west side of the house. This way the sun doesn’t even heat up the windows or the walls. We’ve found that using canvas painter’s drop cloths gives us the right amount of coverage, and it is a lightweight canvas so that plenty of light gets though (just no sun).


  20. Lucas says:

    @#11 wren

    It will not cause any issues with the dual pane windows. Dual pane windows are (generally speaking) better then single pane windows at reflecting solar energy. Most dual pane windows contain a gas between the panes which helps to insulate the windows.

  21. Amanda says:

    Wren, maybe you could just put the blankets or foil or whatever you choose outside the house.

  22. Carol says:

    What prime timing! I’m at point of purchase of some Gila solar film for our scorching hot west-facing windows in western Missouri, but this sounds way cheaper and easier. One objective in addition to heat reduction is screening UV rays to protect a quilt I’ve toiled over for many too many hours. (Moving the bed is not an option.) It seems like the solar blanket trick would work. Anyone think not?

  23. Callie says:

    I agree with the commenters about the outside placement of the window covers. I have an additional suggestion. I took a ‘drawing and invention’ class at the University of Florida. At the time I was dating my husband who was in architecture school. His classes were in a stepped building that had it’s long side facing south with huge windows and balconies. I designed a shade made out of white fabric (cheap fabric shower curtains) and pvc pipe. These awnings cooled the class space but at the same time provided tons of ambient light. I used meters to measure the cooling effect and the light gain, but that was ages ago so I no longer have the numbers, but I must say the effect was significant. Still in FL. To this day I put my windshield cover on the outside of my car.

  24. Razmataz says:

    A few years we did this to some of our window’s, but I did have to take some of them down. Recently we put some of the dark car window film on some of our window’s and I like it a lot better. We only put the film on the part of the window that opens. I like how we can open up the curtains and not a lot of the sun comes in and you don’t get the glare.

    Last month our electric bill went up by $12.00 and since I live in Texas I don’t think that is a big leap in the bill.


  25. Luke G. says:

    My wife recommended to a friend of ours that he put up aluminum foil on his bedroom window. A few days later his landlord ordered him to take it down and he inspected his whole apartment for drugs because (his words:) having aluminum foil over your windows is a ‘sure’ sign of drugs.

    I don’t know what this means, or if this is a ‘sure’ sign in other parts of the world, but be careful if you live in a rougher part of town (where our friend lives is not a very good area).

  26. Joan says:

    I am doing the same this year but have had a problem. The solar blankets have apparently out-gassed and interacted with my off-white cotton curtains, yellowing them considerably. :( These are in my bedroom. I hate to think what may be happening inside my lungs as I sleep.

  27. tarynkay says:

    If you’re concerned about blinding your neighbors, you can also accomplish this with sheets of styrofoam or foam-core. This will just look like white blinds from the outside. I did this in my old apartment with large sheets of salvaged foam core. I clipped binder clips to the edges and hung them on nails. This way they could be easily removed at night to let the cool(er) air in. Ideally you want to hang them so that there is a little space between the window and the blind- the airspace adds insulating value. It is more effective if you can block the sun from outside of the window, but that isn’t always possible, especially if you live in an apartment.

  28. Sam says:

    Great idea – those blankets are much sturdier then tin foil. I’m sending this to a friend in Ca.

    I have a huge west facing picture window that was making an entire section of the house an oven although not anywhere near as hot as Florida.
    2+yrs ago I found a snow white queen or king size thermal/felt type blanket on clearance at the dollar store with some flaw that didn’t matter to me. I roughly hemmed the blanket & hung it between the curtains & the window with a piece of wire (the wire is wound around the curtain rod brackets). I originally was going to take it down in the winter however, the added privacy, no one can see inside at night now, has caused it to become a permanent fixture.

    I’ve since done this same thing, with a dark blanket to block a street light, in the kids room & drove a long sinker type nail in to the wall near each curtain bracket & used that as the wire anchor. I unwind one end of the wire to change or wash the blanket and I don’t have to worry about the curtain rod falling from the weight. this is more permanent but it stands up to kids moving the blanket to look out the window, hiding behind it, etc.

  29. Joanna says:

    Awesome hack. But I hope you’re not thawing meat outside your refrigerator. If you have to thaw meat quickly, you should place the package in a sinkful of cold water. Otherwise, bacteria may develop.

  30. Eileen says:

    This also works in the winter for those of us who have COLD winters. Slows down warm air leaks to the outside.

  31. Vladimir says:

    Pictures please!

  32. Gretchen says:

    I’ve also recently read about using the foam sheets someone mentioned above to block off glass sliding doors in the winter from drafts.

    I was also thinking that instead of hanging the runner’s blankets from sheets you could sew a channel to insert the curtain rod and roll them up like a valance.

  33. I’ve been doing the solar blanket thing for a couple of years, and it makes a huge difference. The blankets are better than tin foil because they let a little light through, they’re window-sized rather than in narrow strips, and they’re flexible enough to fold and unfold without splitting.

    But I was too cheap for tension rods – just put a hook in the wall at each end of the top of the window frame and little rings at the top corners of the blanket. When the sun isn’t beating on the window, I just unhook the rings, loosely fold up the curtain, and stuff it under the nearest chair or table.

  34. Dottie says:

    I also live in Central Florida and have to deal with the awful heat of summer. (love the winter though!!)
    Our guest room gets scorching sun all afternoon and has a very large window. I took a piece of blue R5 Styrofoam insulation sheet ($11.00 @ lowes), painted it white on the side that faces outside and then put it behind the existing white wood blind. It made a huge difference in the amount of heat entering the room and looks nice. From the outside it looks like the white blind and since it is behind the blind you do not see it at all from the inside. There is even enough room behind the blind to add another sheet one day( I think that would make it R10).

  35. Kevin says:

    I recently purchased a roll of Gila brand heat reflecting window film from Home Depot (you can search their site to find it). It was about $30 but worth every penny. I don’t have central air and the windows in my kitchen get brutalized by the sun all day. The difference is simply amazing. It doesn’t knock down the amount of light as much as you might expect (nor does it change the color of the light) but boy does it reflect the heat! I can hold my hand a couple of inches from the window in the direct light of the sun and barely feel anything. It may not be the cheapest solution but it’s worth the few extra bucks because it looks very nice and you can see trough it too. I’m telling you try it and you won’t regret it. :)

  36. littlepitcher says:

    Dollar reflective windshield insulating shades also would work well for this. I have cut them down and used them in every window of a PU to keep the truck’s contents cooler while at work.
    If you use reflective insulating foil, be sure to get the non-permeable variety–some have pores.

    Wish I’d known all of this when I lived in the Hell and Humidity state. Thank you for sharing!

  37. susan says:

    I love this idea. I think we had tried aluminum foil in the past w/minimal effect, but I really think we will try this w/perhaps a combo of blanket or even toweling as others have suggested. We have some very warm south and west windows even w/trees to help block that makes it miserable in the upstairs… Thanks again!!

  38. SimplySara says:

    We have actually done this while desert camping for years but I never thought to do this at home. Excellent!

    In case anyone else enjoys tent camping in the summer, at least up until the point your tent becomes suffocating as the sun rises, I will explain how we do this with our tent. We took an old sheet and some of these reflective blankets and laid them against the fly cover of our tent, and traced the sections of the fly according to the seams of where the poles fit. Then we cut identical panels of both the sheet and the blanket that were approximately 1 inch larger on all sides than the actual fly. Then we duct taped the sheet panel to the reflective blanket panel (we taped the edges together. because we camp in an area that often has winds up to 50 mph, we had to make sure there was no space for wind to get between the panels. You may not need to go through so much trouble, but then again, our panels have lasted for 7 years with 4-5 camping trips per year). Without having the fly on the tent, we secured the panels to the tent, reflective side out, with binder clips (make sure to only have the binder clip against the duct tape. The clips can easily tear the reflective blanket). We don’t put the fly on but we do put the tent under a 10×10 shade structure. The temperature remains cool enough that we can sleep until noon, covered, even when the outside temperature gets to 115 degrees.

    The downside to this system with desert camping is that the temperature can fluctuate widely overnight with temps being 40 degrees in the dark and then soaring to over 100 in the morning. Well, we solved the problem by bringing a second tent. Our cool, day tent is much smaller than our all purpose tent (which has all of our stuff in it) and the smaller tent only has an airmattress and some bedding in it. We face the two tents opposite each other and then when the large tent becomes too hot, we crawl into the cooler tent.

    Incidentally, the panels also work wonderfully for sealing in heat when you flip them(which we learned when we went desert camping in the middle of August only to have highs of 70 and lows of 20). In this instance we flipped the panels around so that the sheet side faced out and the reflective panels faced in, then we put the fly over the panels. Our hot and cold tents were then reversed.

  39. Nebula61 says:

    I love this idea!!! We have a South Florida SW facing back yard and we can’t put up awnings because of the Housing Association we live in (yes, in Miami, we aren’t allowed to use awnings–can you believe it!) and we don’t want to plant trees because we have a lake
    view, so this idea is perfect for us! We haven’t installed window film because of the hassle and because we probably aren’t allowed to do that, either. Many thanks to the original writer for the suggestion and to Trent for forwarding it.

  40. Bill says:

    Several people have mentioned it, but it is much more effective if you block the light on the out side. It does not even need to be reflective. We have roll up synthetic bamboo covers. If you use solar reflective materials on the inside it will work poorly if you have windows that are newer than single pane windows or really cheap windows. As most modern windows are designed to keep thermal energy inside during the winter months.

  41. kay sartin says:

    Thanks very much for the tip. Just want I needed!

  42. Larabara says:

    I have a large West-facing window and a small South-facing window in my living room, but there are a many plants that are flourishing there. I like having lots of plants to purify the air in my home. And they also look nice.

    Would the solar blanket reduce the sunlight to the point that the plants will suffer? If so, is there an alternative to the solar blanket that will make sure that plants get their sunlight without the heat of the sun coming into the house?

  43. Rose M says:

    Some years back we got radiant barrier insulation for our attic (very old house) – same concept. Looked and felt like thick foil. It does make a big difference.

  44. cj says:

    I use those solar emergency blankets in my car as sun reflectors- I keep them as part of my emergency kit anyhow.

  45. Annie says:

    I have the answers! call 877-NRG-SOLUTIONS. They are introducing the In’Flector and Solar Selective window insulator. It has been tried and proven in Canada for at least 20 years. It is a passive solar collector in the winter and reflects all the heat and harmful UV rays in the summer PLUS you have your full view out your window. I mean what good is a window without being able to see out of it? If youre going to cover it with foil u might as well board it over and insulate it. And if you’re thinking of replacing your windows for more efficient ones, this is cheaper and does a better job than any window can ever do. Give them a call…they are very helpful and go out of their way to meet your needs!

  46. I’m not sure if it has been suggested by other commenters but have you tried using Heat Reflective Paints? Doing so will reduce the heat your home is getting thus saving you some money from your AC.

  47. Katrina says:

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  48. Energy Savings with a Solar Blanket, Hair Clips, and Curtain Rods – The Simple Dollar

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