Focus on airsealing which is usually more cost-effective than adding insulation.
I disagree with the R values given for straw/clay and hempcrete. I would bet most of these mixes average between .75 and 1.5 per inch... pretty lousy.
The framing in most homes represents a 25% drop in R values because one is only insulating the cavities between them. A much better insulation strategy for walls is to add continuous sheets of insulation to the outside of the framing or structural members. This usually only makes sense when re-siding.
I typically argue that almost ALL insulation is eco-friendly because it does such a good job of lowering one's main source of a home's environmental footprints: heating and cooling. The damage from these on-going monthly energy and environmental costs usually vastly eclipse the damage from "less environmentally friendly" forms of insulation.
Have to reiterate air-sealing here. Many insulation resources are wasted by ignoring how airtight the structure is...This is probably the most cost-effective strategy to reducing energy and environmental costs, increasing comfort and decreasing the risk of mold, rot and structural decay.
Just a semantics issue that relates to the culture of "air tight" architecture vs natural/traditional permeable/breathable culture in architecture.
Please point me in the direction of the difference of "air sealing" and "draft-proofing"? I don't want to change my terminology here if there is no difference. Air tight homes can also be vapor permeable.
I was speaking of "spun glass" which I will get to at the end of this post.
I didn't bring up the "pink" form of insulation but since you did, I disagree depending on the details.
Read the last line of my last post, you confused my meaning as for modern insulation I like many of the "foam" applications and they are getting better with products like "aircrete" and the related soybean base urethane.
My point was that exterior insulative sheathing is a far more powerful R measurement than cavity R value. If you dont want to use foam, use mineral wool which also has a high embodied energy cost, perhaps more than foam?
Brian Knight wrote:I think most researchers find fiberglass R value actually increases in cold weather.
Brian Knight wrote:Ive always wondered why or how FG R value could increase in cold weather with the convective airflow problems it has..
I think loose fill fiberglass is one of the best things available to anybody, including those interested in permaculture, to decrease their energy and environmental costs in the right applications, mainly attics. Its cheap, readily available, fire resistant, mold resistant, and requires no specialized skill to install.