> Or is this a case of operational costs being ignored in favor of capital costs? I would lean more towards this. Because big windows cause solar gain in the

> Or is this a case of operational costs being ignored in favor of capital costs? I would lean more towards this. Because big windows cause solar gain in the summer, and you have huge losses of heat in the winter in more northern climates: even the absolute best windows maybe reach R-8 (U 0.125), while even sucky walls probably get R 20 or better (U 0.05).