Re: This Old "Green" House on PBS

cdinopassas -- two green options for insulating existing enclosed wall cavities are blown-in cellulose and soy based spray foam.

You can read a little about them at http://www.thegreenguide.com/doc/107/soyinsulation.

The problem for you is that you have an older home with very little space between the brick and inside frame for insulation. I'm by no means an expert in this area, but I'm wondering if the cost of adding insulation to that small space between the walls is really going to be worth the expense.

See http://www.askthebuilder.com/610_How_to_Insulate_an_Older_Brick_Home.sht....

If you find that insulating the walls is too expensive given the benefit, there are a lot of other improvements you could make. You could add insulation to the attic, replace your windows, seal cracks and crevices, etc. If I had a house like yours, before I committed to insulating the walls, I would have a home energy audit done to determine the most cost effective ways to increase the energy efficiency of my home. If you decide to add insulation to the attic, I would recommend hiring a licensed professional to do the work -- older homes can have asbestos insulation in the attic that should not be disturbed. Good luck with your home improvements.