Rigid foam on the exterior of a home or commercial building is a very effective method to increase the insulation level of a home and to eliminate most of the thermal bridging through framing. Here's a cool website witha video on how to properly install exterior building insulation foam.
This is another local business and a member of the Franklin County CDC. They install cellulose insulation made from recycled newspapers. It is non-toxic, fire resistant, mold resistant, sound deadening and rodent deterring. If we find we need supplemental insulation in our house we are going to call upon this little family run business.