Blinded By The Difference
Most of my articles have something to do with saving energy, and this article is no different. In this article, I wanted to talk about the single largest area of our homes that is wasteful of energy, and it is so large and so apparent that most people never even consider it. Our attic? No. Our appliances? No. Our lights? No. It is our windows.
Consider your house as an envelope. We’ll call it our thermal envelope. The parts of it that keep the cold (or excess heat) out are the floor, the ceiling, and the walls. In terms of simple square footage, your walls make up a much larger area than does your floor and ceiling combined. Your walls are exposed the most to the frigid northern winds during the winter, whereas your ceiling is mostly protected by the roof, and the floor is not exposed to the winds. Your walls can, at this latitude, take a direct pounding by 100F+ degree heat for 8 or more hours in the summer months, especially on the western side of the house, whereas your ceiling is once again mostly protected by the roof and the floor is not exposed to the sun.
So, let’s focus on the walls. Walls are measured with an overall “R” value. An “R” value is simply a number that is assigned to a material’s ability to insulate, or to resist hot or cold. The measuring stick is simply block of wood. A piece of wood that is one inch thick has an “R” value of “1”. So… a piece of wood that is one inch thick has an insulating value of R-1. This is what all other insulating materials are judged against. The type of insulation that is most commonly in the attics of the homes in Idaho is a loose fill fiberglass. This type of insulation has a rough value of R-3 per inch (some types are 2.5, while others are 3.5). So, let’s say you have 10 inches of loose fill fiberglass in your attic. You have an insulating value of roughly R-30 in the attic. In times gone past, that was considered enough. But, the US Department of Energy has recently revised their “R” value standards. These are very interesting, and can be seen on their web site.
Back to your walls. Most walls are built with 2x4 studs during construction. The area between the studs is typically filled with fiberglass batts. This normally gives your walls a rating of about R-11. Many homes are now being constructed using 2x6 studs… providing an “R” value of R-19 (or so). Look around at your walls. Better yet, measure them on the outside of your house. Figure out how many square feet of wall space you have. Then, figure out how many square feet of windows you have. You will see that your windows can account for 10%, or even 20% or more of your actual wall space. So, your wall is an R-11 or maybe an R-19… but only that portion of your wall that is not made of glass.
So, what about this glass that makes up a significant portion of your thermal envelope? Over half the homes in this country still have single paned windows. On average, that equates to about an R-1 in protective insulating value. Millions of homes have the old aluminum framed double panes from the 60’s and 70’s. By now, there is likely no airtight thermal seal remaining between those panes and they, too, are worth barely more than an R-1. A good, modern, double paned vinyl window typically rates about an R-2 insulating value. There are a few rare and expensive types that even get to an R-3 or slightly higher. So… it is easy to see that, by far, the weak point in any home’s thermal envelope is the windows.
So, what to do? How do we address this issue? Planting certain types of trees in the right locations can help a bit when it comes to strategic shading, but it does nothing to address the insulating value of the windows. Replacing all your windows can be horribly expensive. Yes, it will reduce your energy bills and make a more comfortable house, but what you save in energy each month might often take 20 or more years to recoup the cost of the new windows. In other words… how long does it take to make them pay for themselves. Only a real good energy audit can determine this. Window salesmen will, of course, tell you the recoup time is much much shorter, and it can indeed be, but the norm is 20+ years. Is there a better way?
An important thing to remember regarding insulation: it is that it is not the fiberglass (or the glass) that is does the actual insulating… rather, it is the air that is trapped within the fiberglass. That is why modern double paned windows typically rate an R-2 value, whereas a single pane might make it to an R-1 value. Air is the key. Air itself is a fantastic insulator. A single inch of still air has an “R” value approaching R-5. That’s right. A single inch of air can be almost 5 times more effective at insulating than an inch of wood. The trick is to turn air into any ally in making your windows more energy efficient. Take a wool blanket, or a thick towel, and simply tape it up over the inside of one of your windows. You will immediately notice the difference. The air between the blanket and the glass instantly becomes an insulator. Not a practical solution I agree. But just try it and you’ll be amazed at the difference.
There are numerous shade/blind companies out there that are finally realizing this and are capitalizing on this phenomena. You can now find shades that are not only attractive, but are made of a modern synthetic fiber that has good insulating properties. Some blind companies are going even further, and they make blinds that fold compactly, but when extended, they form a pleated pattern that basically creates an air pocket in between each individual fold of fabric. Here is the increase in “R” value. Some blind companies have taken this a step further and have made the individual pleats in such a fashion that they actually create two layers of air pockets in between three layers of pleat material in between the glass and the inside of the room. The “R” value jumps again (air = insulation). The problem is… there is a small gap where the left and right ends of the blinds do not quite touch the window frame. There is also the small gap at the bottom here the bottom of the blind does not quite touch the window sill. In the winter, heat escapes from your house through these gaps and greatly reduces the “R” value of the pleated shade.
About a year ago a friend of mine told me about a company in Northern Vermont that has tackled this problem. They are called Symphony Shades. What they have done is create these plastic tracks that you mount on the inside of your window frame. They have a small plastic ridge that fits into a notch cut into the ends of the pleats. You can hardly see these side tracks, and do not even notice them unless one is looking closely at the window frame. These side tracks eliminate that “R” stealing gap that occurs naturally with traditional blinds. When installed, these side track blinds add an “R” value of 4.6 to your thermal envelope!!! So, your single paned windows that might have an “R” value of a “1”, are instantly transformed into something that has 400% more insulating strength than the glass alone. Or, your double paned windows (like exist on my home) suddenly go from an R-2 to nearly an R-7!
These side track blinds can be a bit pricey, especially on the larger windows. Initially, I started buying just one at a time in order to minimize the burden of cost. I recommend you purchase just one… and install it in your bedroom. Your room will be instantly much warmer in the winter months, and you’ll be able to turn your thermostat down without reducing your comfort. In the summer months, you won’t need the air conditioning as much. I am certain that you’ll be so impressed, you’ll do like I did and outfit the entire house with them. These blinds have reduced my monthly heating and cooling costs by about $30 per month. The money I save on utilities will pay for the cost of these blinds in only a few years. So, instead of a 20+ year cost recoup time… I am looking at recouping the cost in less than 5 years. After that, they are just money in the bank.
These blinds are real easy to install, after you figure out the first one. The first one takes a few moments because these side tracks are unique and they take some time to visualize and get them on properly. What about looks? They look fantastic! The come in a great variety of colors and textures. They even include options for blackout shades if you want to outfit a movie or media room. Also, they include options for reflective shade… great for windows that face the long beating of the summer sun (radiant heat) on the west side of the house.
The thing that impressed me the most with this company is their service. All of the blinds I ordered from them were exactly what I ordered and they all fit perfectly. About seven months after installing one of the blinds, it developed a problem in the retraction mechanism and would not allow the blind to go up or down. I sent them an e-mail asking for advice on how to repair the mechanism. They mailed back to me a UPS label for company paid shipping… asking me instead to send the blind back to Vermont, so I did. Yesterday, I arrived home from work to find my blind had been returned to me in full working order. No questions asked. No cost. This is what has impressed me the most. These people operate their business with old fashioned American values. A good product at a fair price. American made… American backed. With fantastic service… standing behind their product.
So many companies these days have lost sight of what has made all that is great in America. They offer cheap products and have disclaimers for every possible contingency. Symphony Shades has taken traditional New England craftsmanship and ingenuity, and combined it with an ethical standard that is all too often seen lacking in today’s business world. I am here to tell you that this is a company you can trust, and their blinds are worth their weight in gold. See them on the web where I found them, at http://symphonyshades.com/
Oxbow Home Inspections
Sunday, January 25, 2009
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