Part of my thought process as well, begreen. I am slowly remodeling as I can and am reinsulating as I go. I guess I dont really expect the unit to still be producing usable heat when I get home, just enough coals for an easy restart to get it going good before I head off for bed(I'm a 2nd shifter).To get back to the OP's question. Personally I would consider getting the 30NC and putting the savings into improving the house sealing. $1000 can buy a lot of caulking material and even some more insulation. Tightening up the house is a win-win solution. You'll burn less fuel and be more comfortable.