We want to bump out exterior walls that face our northwest view to create a dining nook beyond the kitchen and a home office beyond a seldom-used walk-in closet. Both additions would be 8' x 8'. To maximize the view I'd like fixed-pane maximum insulated windows about 7'h x 6'w on all three walls of both room additions. How much extra in initial cost and heating bills would this cost over 4'h x 6'w windows?
For the home we'll be building in Rapid City, South Dakota, we'll have a central heating & cooling. However, the guest wing has two bedrooms with a shared bathroom. We estimate we'll have a maximum of 20 to 25 days per year of guest use. Is there any savings over a 10-year period in having a separate heating & cooling unit for that wing?