*Blackout Curtains*
Purpose and Application of Blackout Curtains
By: Centurion
26 December 2011

What are Blackout Curtains?

Blackout curtains are specially designed and constructed to block out 99.9% of the sun's light and up to 100% of UV rays. However, they typically work to block both incoming and outgoing light. If you install blackout curtains, you can have more confidence that the light inside your house will not be seen outside if you wish your house to look private, dark or even unoccupied.

History of Blackout Curtains?

Blackout curtains first became common (even required) during World War II in England and other parts of Europe. Especially during the Battle of Britain, aircraft navigation techniques and even bomb sights were largely visual. Pilots and navigators would follow compass bearings to their targets, but would often verify their position and flight path based on the lights of known towns and cities expected along their path. The British military would often black out entire towns at night using blackout curtains, and then set up fake towns using hundreds of lamps set up a few miles away in the middle of empty fields. The bombers would occasionally bomb these empty fields because the light patterns were laid out to match nearby targets.

Why Have Blackout Curtains Today?

There are many good reasons to invest in blackout curtains for the modern home. If you ever need to sleep in the daytime (such as working nights or a fussy baby), these curtains help simulate a night time environment any time of day. They often have the added benefit of reducing noise coming in from the outside.

Blackout curtains provide exceptional privacy to bedrooms, bathrooms, etc., where normal shades or curtains would allow silhouettes to be visible to strangers walking down the street.

As homes become more energy efficient, windows often continue to be a source of low efficiency. Blackout curtains often have thermal properties which stop sunlight from heating your home during the summer and minimize heat loss through the windows during the winter.

Additionally, home hobbyists who enjoy photography or home movie theaters often use blackout curtains to control incoming outside light, but allow rooms to be quickly converted to normal use and lighting by opening the curtains.

In a survival situation, there might be a number of reasons to black out your home. For example, last summer a storm blew through our area and knocked out the power for a day or so. During the first evening, I walked outside and noticed one of my neighbors across the street had lights. And, from the sidewalk, you could even see the blue-ish flicker of a TV or movie against the shades. Based on the sound I heard, I guessed my neighbor had a portable generator sitting on his back patio. As is often stated, during a short power outage, your neighbors will notice who has power. And, while they might not bother you on the first day, you can bet they will be asking to share your power within a couple of days. And, had the power outage been longer (or permanent), you can bet a number of neighbors would have been knocking on his door. However, an inexpensive set of blackout curtains would have eliminated the visual clues about who has power on our street. (Noise dampers for the generator must be dealt with in a separate article.)

Commercial Options / Approx. Costs...

There are many styles, colors and designs for blackout curtains commercially available. They can be found at Amazon.com, Walmart, Target, and at numerous online retailers who specialize in blackout curtains. Try typing "blackout curtain" in any search engine to get a host of results. I have found most curtains start at around $20-$30 per window and move up to about $75 per window.

Non-Commercial Options...

If you are on a serious budget crunch, or need to black out your house NOW without the benefit of going to the store, there are still some options... although not as attractive and possibly more noticeable from the outside. In my testing, I went outside at night and stood within 10 feet of the window. In a completely dark environment, even small holes or cracks, which are difficult to locate from inside, become very bright. Keep in mind that it only takes ONE spot of light for someone to realize you have power when the neighborhood is dark.

  1. Plywood and caulk. No, it isn't pretty, but it is functional and relatively fast. If you want something that might be a little more "urban camo", you could paint the plywood to match the outside of your curtains or blinds (probably white), and then paint lines or shadows to simulate mini-blinds or curtains as viewed from the outside. I haven't done this, so your creativity and mileage may vary.

  2. Blankets. Blankets can be hung over the windows and nailed into place. After installation, someone should go outside and check the effectiveness of the technique and material. In my own initial testing (which, unfortunately, I forgot to photograph), the blankets were not as effective as I expected. It was especially difficult to eliminate the halo effect around the edges without at least 8-12 inches of window overlap all the way around. Also, thinner blankets which we use as "throws" on the couch, were almost useless.

  3. Paper bags. I tried brown paper sacks, which were once common as grocery bags. These worked pretty well using multiple layers. Unfortunately, due to their size, there were a lot of seams that required taping and re-taping to stop all light leakage.

  4. Black plastic rolls. A roll of black plastic worked pretty well. I tested a very heavy mil plastic which is often used in the garden for weed control. This stuff was almost as thick as an MRE package. It worked well, but again I ran into the problem of seams. I had to really overlap the seams and applied two or three layers of duct tape to ensure no light leaked through. It was also very obvious from the outside because no one in our area has solid black windows or curtains. Again, they worked, but during the daytime it would be obvious you were trying to hide something.

  5. Anything white... doesn't work. I tried 'butcher paper', bed sheets, notebook paper, newspaper, trash bags, etc. I found that white colored products, unless designed to stop light (like blackout curtains), don't work well. They might reduce the light and shadows, but create a glow effect which doesn't hide much light at all.

Installation and Use...

In most situations where you are simply trying to sleep or would like to ensure your privacy, having a little light leak OUT from your house is not a big deal. However, in a survival or power-grid-down situation, any light leaking out might be a giveaway that you have power.

So, when installing these curtains, make sure they overlap the window on all sides enough that light will not 'leak' around the edges. In a true survival situation, I have found through testing, that it is a good idea to use some handy duct tape around the edges of your blackout curtains to secure them to the wall and ensure no light escapes. Otherwise, from the outside you can see a slight halo around the edges of the window where light is escaping from inside the room.


Blackout curtains today are aesthetically attractive and come in a variety of styles and colors for any décor. They provide a number of benefits inside the modern home including privacy, energy efficiency and complete light control. The cost is also low enough that they can be incorporated during a normal room redecoration, without significant pain to the budget. However, in a power outage situation, where you are the only one on the block with the foresight to have an alternate energy solution, they may reduce or eliminate the number of knocks on your door by a neighbor with a very long extension cord.

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