Spray foam insulation is one of the best options for increasing the energy efficiency of a home. It is air-tight, and closed-cell remains the only FEMA approved flood resistant insulation. Despite it's resilience and efficiency benefits, spray foam is not the most sustainable option. Chemical off-gassing from diphenyl diisocyanate, or MDI, has been linked to health concerns including asthma and lung disease. The synthetic chemical is found is spray foam as well as adhesives like gorilla glue. The EPA has yet to regulate MDI in products, so in the meantime consumers are on their own to find and install sustainable alternatives. Here are four options for greener, effective insulation.

1. Soybean-based spray foam: Although it has a similar R-Value, soybean-based foam does not contain MDI. Biobased and Demilec are two of the leading manufacturers of soy-foam.

2. Castor oil-based Icynene: This additional form of chemical-free insulation is even a spray foam, but without MDI.

3. Cotton denim batting: Denim insulation is typically produced in sheets from recycled clothes or industrial materials. It works similarly well to spray foam, but can cost about double and is not quite as easy to install. For new construction, however, this green alternative to spray foam has a lengthy life span.

4. Sheep's wool insulation: Like denim, this green alternative to spray foam cannot be blown into walls, but is a chemical-free alternative to traditional foam insulation.

Read more about green alternatives to spray foam from Fairfield Citizen.