All of the costs go up with a complex plan. Another thing people don't factor in is the increase in wall area, which equates to energy loss. One of my favorite designs was a cross-gable house. I figured out that it had the wall area of a house that was nearly twice as big! Round would have the very least wall area, followed by square. We wound up building a fairly wide rectangle.

A factor to consider when insulating is also what the upfront cost is, compared to the payback. Many of your edge and crevice issues are easily addressed by installing foam insulation. Foam gets into every nook and cranny if done right.
There are many arguments about foam, but we installed it in our new build. If it works as it is purported to work as far as energy savings, along with our metal roof- those will be the two greatest investments we make in our comfort and economy over the next years.
(edited to add a foam pic)
It is expensive upfront.

This post was edited by musicgal on Wed, Jun 4, 14 at 13:14

mg....what are those 2 large pipes going thru the basement floor?

Normally insulation companies charge per sq ft of wall - so really does not make any difference. Outlines increase cost of foundation, roof plains, flooring (increases the waste), etc - as far as insulation I disagree.

When you submit request for bids - you just say 4000 sq ft of wall insulation fiberglass R15 and 2500 attic at blown in fiberglass R38

Hi Robin- attic, not basement:-) They are solatubes. They bring in captured sunlight from the rooftop into the kitchen.