Embodied energy is the energy consumed in producing products. Mineral insulation comes from furnaces that gulp natural gas to melt sand, slag, or rock. Foam plastics are petrochemicals. They are literally made out of energy! Cellulose insulation is made by processing recycled wood fibers through electrically driven mills that consume relatively little energy when they are operating, and which can be shut down completely with the flip of a switch at the end of the shift -- or even for lunch and coffee breaks. Fiber glass, rock wool, and plastic insulation may have from 50 to over 200 times more embodied energy than cellulose. Preferred Building Systems, our modular home factory installs dense-pack cellulose at a 3.8 per inch R value and provides tremendous air sealing along with the additional air sealing we install. The cellulose is 85% post consumer recycled newspapers with a fungicide and fire retarder. ________________________________ From: VGBN Discussion [mailto:[log in to unmask]] On Behalf Of Suzy Hodgson Sent: Thursday, December 11, 2008 1:03 PM To: [log in to unmask] Subject: Re: not natural building products? cellulose insulation made with recycled paper is a good green option with performance - high R value and low ghg emissions On 11 Dec 2008, at 12:55, Robert Riversong wrote: Icynene vs straw is a good example of the difficulty in making appropriate choices of "green" materials. While I don't think that spray foams should be used in new construction, stuffing straw into existing walls for a retrofit/upgrade is not a sensible option and with a limited wall cavity Icynene may be the best alternative for renovation. Even for new construction, straw bales - with their low R-value per inch (—1.45, about the same as lumber) may not be the best choice. Besides having no global warming or ozone-depleting installation by-products, Icynene has only a little more embodied energy per cubic foot than fiberglass (not that I would recommend fiberglass for anything), typically less installed embodied energy (since framing bays are not generally completely filled) and better efficiency payback. Best use of remaining fossil energy and petrochemicals? Not so simple to discern. --- On Thu, 12/11/08, Michelle Smith Mullarkey <[log in to unmask]> wrote: Point taken. I admittedly was thinking of products like Icynene vs. straw, but it seems fossil fuels really are part of our entire world. On 12/10/2008 6:21 PM, Robert Riversong wrote: --- On Wed, 12/10/08, Michelle Smith Mullarkey <[log in to unmask]> <mailto:[log in to unmask]> wrote: Fossil fuel is still used to manufacture and transport the majority of green building products (not natural building products such as straw bales)... I'm afraid that fossil fuels are used for the production of most straw and since some of it is coming from Canada, there's also transportation costs. "Natural" building materials are not necessarily immune from the environmental costs of other materials.