[vonsmog]

Most heat loss is out the ceiling (heat rises), so attic insulation is more important than wall, as windows have a "R" value of what, 2. So what good is it having walls with a high "R" value next to a bunch of windows. When I built my house 24 years ago we used 2X4 for most walls and 2X6 where plumbing would be in the wall. We have over 60 windows in the house so high "R" value for the walls would be a waste. So we have "R" of 19 for most of the walls.