Energy Efficient Design Priority: How Airtight is an Eco-Friendly Home
The most important energy efficient design issue is how well a home is insulated and sealed to prevent open pockets of air. Time, diligence, and even money spent to cover this facet of building an eco-friendly home will save energy and money in the long run, and make expensive heating and cooling options impractical and unnecessary.
There are many different insulation materials to choose from, some with a negative impact on the environment, and others with a more subtle green footprint. Fiber glass for instance, is the most commonly used insulation material used in homes. It can be an irritant, and during manufacturing there are formaldehyde emissions. This chemical, which is a known carcinogen is also present in the material when used as insulation, and should be safely kept behind walls.
Air krete on the other hand is one of the most eco-friendly insulation materials. The magnesium dioxide from sea-water and ceramic talc, air krete has negligible impact on the environment in manufacturing, is safe for home air quality, and is incredibly fire and mold resistant. Both fiberglass and air krete are good insulation materials, although air krete has a consistent R-value (a material's resistance to heat flow) of 3.9, while fiberglass varies from 2.2 to 4.0.
Aside from good insulation for an eco-friendly home, energy efficient living requires the an air barrier to block air flow from entering and exiting the home. This could mean a continuous layer of polyethylene, an extra layer of drywall, or a layer of rigid foam insulation with edges and joints carefully sealed.