We now have the proper insulation (see pages 24 and 28) that the furnace REALLY needs; (we and everyone else has been doing it wrong according to the insulation engineers!)

We now have insulation with R-23 in the sides and R-57 in the front against the 700 degree firebox with up to R-88 optional EXTREME Cold Weather Package!

Superwood Insulation (white) up to R-88;
with the 3 inch Extreme Cold Weather Package