A Green Way to Insulate for Extreme Energy Efficiency

Posted by Rob Nicely on December 09, 2014
A Green Way to Insulate for Extreme Energy Efficiency
Rob Nicely, president of Carmel Building & Design explains their insulation choice further in a video.

Back in the '70s, California’s Title 24 revised the state’s building code to include limits for energy usage in built environments. The go-to solution for stemming the amount of energy required for heating and cooling quickly became insulation. For decades, the most frequently used type of insulation was fiberglass batt, laid between framing in walls and ceilings. To work effectively, insulation has to completely stop the movement of air. The fiberglass itself is not the insulation—it’s the material’s ability to trap air—known in the trades as the “dead air space strategy.” The primary challenges have been installing it in a way that completely fills all the cavities, and protecting the installers from skin rashes and breathing the harmful particles that escape during the process.

As an alternative, many of us turned to blown-in foam as insulation because it’s much better at perfectly filling the cavity. While foam does an incredible job of insulating and creating a thermal boundary, it also comes with drawbacks. The accelerant can be harmful to installers and special protective gear is required. It also produces greenhouse gasses that lead to depletion of the ozone layer.

Today, insulating is a “no brainer” in the building process. And we’re diverting that extra brain power into developing materials and strategies that are safer for people and the environment, yet significantly more effective. For insulation in our Carmel Point project, following protocols of the Living Building Challenge, we’re using two innovative products—blown-in cellulose and rock wool. Cellulose, made of at least 80% post-consumer paper waste, is blown into all the spaces between framing on interior walls and ceilings. It doesn’t require the harmful accelerants of blown-in foam. Rock wool, a by-product of steel smelting, is formed into rigid boards for insulation over exterior framing. On top of being a super-insulator, rock wool also repels water that can cause damage to the structure and negatively impact interior air quality, over time.

Products like these, and those to come in the future, turn waste into viable materials that keep us on the path of responsible, sustainable building.

Check out this and other green building videos on the Carmel Building & Design site.

Rob Nicely is the president of Carmel Building & Design. If you have questions, send an email to

This blog was reprinted with permission. You can view the original post here.

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