Wednesday, December 9, 2009

Holidays and SIPs

Apologies to my "multitudinous" followers about the lack of posts lately. The busy holiday season is upon us, along with end-of-the-year business tasks, and time for posting has been reduced. For those who are interested, I'd recommend the following to fill your web-browsing needs:

Diverging a bit from my usual focus on retrofits, I read about a simple construction idea gaining more popularity: using the same materials we already build with, but rearranging them a bit, can produce incredible energy savings. Building with Structural Insulated Panels (SIPs) can reduce energy use of a home by 75%. The trick: instead of a wall studs every 2' connecting inner and outer walls with insulation laid between them, SIPs use a sandwich of foam insulation between "slices" of wood, with the wood facing the inside and outside areas. Building the walls this way, while using roughly the same materials, reduces the number of "thermal bridges" (the wall studs) that provide heat a shortcut around the insulation. Although nominally the same R-value as an insulated traditional wall of the same thickness, there are fewer areas that are far below the rated R-value, yielding a true overall resistance to heat flow that can be 4 times better than the traditional construction. Think of it as averaging fewer zeroes for missed assignments (i.e. the wall studs) into your otherwise good Grade Point Average (the R-value of the insulation), and you can see why it works well. About the only downside seems to be that you _really_ need to keep moisture out, or it ruins the foam/wood bond. Experienced construction people should know how to do this.

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