My son just bought a home with a propane gas heating system, (Central Maine) Home is about 20 x 50 with a full cellar. He wants to install a wood stove in his unfinished basement and burn wood to supplement his gas. Gas is very $$$ here. I have tried to sway him to putting the wood stove in the living area, but that doesn't seem to be an option for him. He will have a metal hood fashioned and hang it above his stove (an old Allnighter that heated my home for years). I think I have convinced him that his heat will all but wasted unless he insulates the cinder block cellar walls. My question, is what is the minimum amount and type of insulation to put on his walls. Basement can be damp. Has a full foundation and cement floor with an active sump working. Thanks