Windows give you natural light and solar heat gain, but they are also the most strategically vulnerable part of your home or retreat and largest source of heat loss in conventional construction. The R value (measuring insulation or resistance to heat flow, the higher the more insulting something is http://rvalue.net ) may be an incomplete, and “apples to oranges” number as pointed out by David South of Monolithic Domes http://www.monolithicdome.com/plan_design/rfairy/ but, for my purposes here it does give us a reasonably quantitative basis for comparison. Remember, the higher the R number, the higher the degree of insulation. Here in Wisconsin, builders now try and reach R [insulation] values of 29 for exterior walls, and R40 for attics. People tend to take notice if those numbers are much lower, such as a wall in an old house which is ONLY R12. Yet, people don’t seem to even notice or care that their windows, even the “high efficiency” double casement windows, are but a mere R2 or maybe R3. That, and the transparency of glass for both light and infrared heat, serves to work against you especially if faced with dangerous temperature extremes (survival situations). In the summer, when you want to cool your home, light comes pouring in, quickly heating your home since the thermal mass it shines on is usually inadequate to absorb the energy without heating up substantially. At night, the reverse happens, and the heat goes pouring out of your home through your windows. The other big downside to windows is their vulnerability. Obviously they are easy to break through, unless you use very expensive Lexan or Plexiglas products. Worse, particularly during high winds, tornados, and hurricanes, projectiles coming through non-tempered glass can create a highly dangerous sharp shower of glass for anyone in the line of fire far worse than the original projectile. The rest of this article is to suggest some simple solutions to mitigate the problems of having windows, and to provide numerous links to expose you to some of the products and ideas out there on the topic.
We can start by talking about high efficiency windows, but R numbers are so low, even for the good ones, that it becomes a minor factor against other things you can do. First, at least make sure you windows have tight air seals, no drafts. That exceeds even the low R value of windows problem, especially in high winds. We just want to have to worry about solar and infra red heat gain and losses http://www.humboldt.edu/~ges7/windows.htm so grab some plastic, tape, weather stripping, caulk, and maybe that 3M product you apply and seal with a hair dryer http://besttop.ru/cat495374 and get those windows sealed up tight before you consider anything else.
To keep the warmth out, there are exterior screens http://www.rollac.com/screen.html. A great inexpensive source for items including sunlight controls is http://www.growersupply.com/. Order the catalog, it is so full of great stuff and also goes over using water as thermal mass. This link has been on SurvivalBlog before, and for good reason, get it. There is also such thing as a blast curtain safety drape: http://www.safetydrape.com/options.php#gallery
To improve cold weather energy efficiency, keep the heat in, consider adding triple honeycomb cell pull shades one the inside, giving you a R value gain of R3.3 to 3.8 (the numbers are cumulative, you can add them, i.e. window R2 + honeycomb R3.5= R5.5) A good source is http://www.smithandnoble.com and more specifically the honeycombs here: http://tinyurl.com/3ybq8. Two more European solutions are between the window models: http://www.swissshade.com/fauser_complete_system.htm and exterior roll downs http://www.betterhaus.com/ , or see a US model on the subject for hurricane protection: http://www.rollac.com/shutters.html.
For exterior storm protection, there are new windows made to take greater punishment, and after Katrina this has become a growing market. One example is Silverline’s Weather Stopper series: http://www.silverlinewindows.com/index.cfm. Another shatter guarding product, perhaps even more extreme is http://www.shattergard.com/home.html or from 3M http://www.tropictint.net/commercial.html. Although the idea of fabric is usually to block the sun, a new breed of hurricane fabric shutters for external window protection now exists http://steelframehousing.org/specialty%20products/fabric_shutters.htm
Then there are good old fashion window shutters. This is a decorative step up from your 5/8” Oriented Strand Board (OSB) plywood. If you plan to go the way of plywood though, at least build your frame in such a way that attachment will be solid and quick to do. The extra consideration here is to insulate your shutter (or plywood) if possible, in addition to making them strong enough to do the job. This is another area where there are many new choices with recent high hurricane years http://www.stormshutters.com/, http://www.windshutters.com/, http://www.floridashuttersinc.com/ and don’t forget a good set of hinges http://www.hardwaresource.com/ . Also there are accordion shutters for the inside http://www.roll-a-way.com/products/products.html#Accordion
Alternatives to windows all together include products such as solatube http://www.solatube.com/residential.php or the more extreme idea of “piping” in light, without the heat, concentrated by a collector dish through fiber optics http://pesn.com/2005/07/27/9600139_Fiber_Optics_Bring_Sun_Indoors/ .
So don’t let your window to the world be a gateway for heat loss, unwanted solar gain, or the very unwanted point of uninvited entry. As a closing thought, consider also a quality periscope before you go peeking your face out in the window: http://www.telescopes.com/products/Sportscope_Zoom_4x-9x_Periscope_18172.html This is no toy, it works great. – Rourke website: http://groups.yahoo.com/group/survivalretreat/
