Author’s Note: Many readers have mistakenly read this post as a serious suggestion that we stop insulating our buildings, and friends and foes alike have given me large rations of grief over this, all of which can be read below. I am a longtime advocate of high-performance homes and in no way would I ever recommend that we reduce or eliminate insulation. I do believe, however, that we need to consider the potential health effects of various products that we use and how they will affect our decisions on construction methods. Now on to the original post:
Most readers of this blog know about my problems with batt insulation from my post earlier this year, and I was pleased to read a recent post by Tristan Roberts about problems with denim batt insulation in which he referenced my insulation post. Now spray foam products, the darlings of the green building industry, are under review by the EPA for health problems related to their blowing agents.
And just last month the U.S. Department of Health and Human Services issued its 12th report on carcinogens, classifying inhalable glass fibers (along with formaldehyde and styrene) as carcinogens. Finally, there are concerns with the dust and additives used in cellulose insulation, raising some suspicions about that product’s green credentials.
Most of the familiar insulation products are under mild to moderate clouds. Batt insulation, in general, is a challenge to install correctly; fiberglass is carcinogenic; spray foam may be a health hazard; many rigid foam boards have high global warming potential; and cellulose may have unwanted fire retardants in it.
Among the few remaining products are Air Krete, a limited availability, proprietary cement-based foaming insulation; and, if the fibers are large enough so as not to be carcinogenic, mineral wool — although it is primarily available in batts and subject to the same installation issues as all batt products.
Let’s not forget about wool insulation, available in both batt and blown forms; however, it is costly and in limited supply.
Is insulation the problem?
Before the advent of insulation, buildings tended to be more durable, if not uncomfortable for the occupants. Uninsulated framed wall cavities generally didn’t have durability or mold problems; it is the insulation added those cavities that held moisture in long enough to cause problems.
Do we stop insulating buildings to avoid being poisoned by them? I don’t think average homeowners would want to forgo insulation. Even if it isn’t installed well, it does make a difference.
Is integration the answer?
If we’re not willing to go back to the dark ages of uninsulated homes, our last hope for healthy and comfortable homes may be structural material with integrated insulation, such as aerated autoclaved concrete (AAC). AAC is a lightweight cement available in blocks and panels that are inherently well insulating. There is no wood to deteriorate, and as far as I can tell, the product looks pretty benign, although it does produce a lot of dust when cut, which raises health issues for the workers using it.
Insulating concrete forms made of products like Durisol use mineral wool for interior insulation; however, we don’t have a definitive answer on the safety of that, either. While these materials are good options, they tend to be labor-intensive, costly products to install and are not likely to gain widespread adoption any time soon. In fact, an AAC plant in Georgia was for sale recently due to low sales volume.
What’s a poor boy to do?
Personally, I’m getting pretty baffled by the whole thing. I am finding it more and more challenging to make recommendations to clients about which insulation product to use — let alone make a decision about what to use in my own house, should I ever get around to building it.
Do we want to give clients asthma or cancer, or empty their bank accounts with something like AAC? Maybe it’s just time to give up and move to Hawaii where the weather is perfect.