My house is as insulated as you get, we have 2x6 and 2x8 constructions, Sips on some walls, with the insulation air gap on the others... The house is new, so insulation is very good, its so tight I use a fresh air exchanger to keep the o1 levels around 20.9%.... The size of the house and the design with high celings, huge windows, glass doors ect. makes it an energy hound, If I use oil I can expect to pay $6000 or so, coal can do it for under 2000 easily...