I am getting ready to build a new place- dont know exactly yet whether I am going to use 2x6 stick built walls or an insulated concrete form, but wondering if I go with the 2x wall some suggesstions for having a place that is extremely well insulated. Im going to heat and cool with a heat pump, but electric is still expensive in my area so I want to get that bill down as far as possible. I think I would use blown cellulose in the walls. Would it pay to then put some of that sheet styrofoam over the studs on the inside or outside? What about under the floor joists and in the attic? I have heard that sprayed foam directly over the inside of the roof sheathing is the best for the attic. Just wondering if anyone else has done any of these and how it has worked out.