Green Building: (Some) Insulation's Dirty Little Secret

In the wake of skyrocketing fuel prices during the 1970’s oil crisis, the rise of tightly sealed, tightly insulated homes have dominated in the United States both as a nod to green building and to energy efficiency. Although some green builders have made a conscious decision to use low-footprint materials to insulate houses such as recycled denim insulation and blown-in cellulose, the general consensus has been that insulating houses mattered more than the material with which we choose to insulate said homes.

A recent article in Environmental Building News, however, shows that this thinking has been misguided. They looked at the ecological payback, or how long it takes to recoup in saved energy emissions the quantity of green house gasses released by creation/use of the insulating material, of two common types of  insulation, Extruded polystyrene (XPS) best known by the brands Dow Styrofoam ("blueboard") and Owens Corning Foamular ("pinkboard"), and closed-cell spray polyurethane foam (SPF) and closed-cell spray polyurethane foam (SPF) which is sprayed into building cavities, onto foundation walls or onto roofs. Depending on which material, XPS vs SPF, and the thickness of the material used (the thicker material the better the insulation but the longer the payback) they found that they had ecological paybacks of between 35 and 110 years. As a point of contrast, according to the 2007 American Housing Survey for the United States, the median home age is 33 years.

Their findings are not all that surprising; it’s rare that when the full cost accounting of an item is calculated to find that the ‘synthetic’ comes out on top of the ‘natural’.

Take, for example, the paper versus plastic bag debate. Often, the argument goes both are bad for the environment. And its true both are bad - in an ideal world we wouldn't consume so much disposal waste; but the reality of the world as it exists now paper production doesn't have to be awful. Trees, bamboo, and hemp - all of the stuff paper is made out of are potentially renewable resources, and the paper milling industry is increasingly cleaning up its act. Plastic is at worse predicated on the non-renewable resource of oil and never biodegrades or at best is dependent on agriculture (corn) which comes with its own set of issues. There are not paper bags tumbling down the streets of some developing nations like some modern spin on the Western tumbleweed, nor are paper bags clogging up the world’s oceans.
Natural systems were designed to deal with paper; it would take a team of chemists to get traditional plastic to biodegrade.

Yes, nature is problematic – not all of her fruits are great for us or for society at large. Yet, time and time again, we’ve been shown that the more we tend towards materials too divorced from what natural systems have shown a capacity to produce and disassemble the more unintended negative consequences we suffer.

The question is when will we finally embrace that lesson?