I have good attic insulation and pretty good air tight house due to improvements I've been making. My next venture is to provide better "insulation" against my windows. They say windows are 10â€“25% of a homeâ€™s exterior wall area, and account for 25â€“50% of the heating and cooling needs, depending on the climate (I'm in Sacramento). I currently have 20 yr. old plain 'ol dual-pane windows, with simple venitian blinds and single cell shades. In winter you can really feel the cold coming thru them and in summer I get direct South sun and I bake. So, what would give me a better "bang for my buck", go with Plantation Shutters or replacing my window's with high efficiency loE/argon windows. Plantation shutter's which go for $17 sq. ft. installed, so for me that'll be $8k.