Budget concern: Better to buy the R-10 windows with less-great walls?
A budget crunch forces some tough decisions. Most of the bidders prefer using 2x6s instead of the double stud wall, and using American R-2.5 to 3 windows over the European R-10 ones. My general knowledge is that heat always moves to warm up what is cold, therefore keeping our R-10 windows in the design seems like the place to spend our money. This would mean backing down to an overall R-22 wall (2x6s 24″ oc, exterior 1.5″ Zip System and another 1″ of rigid insulation, well sealed batt or rock wool in the cavity). Alternatively, we could shift the money to get spray foam everywhere if we went with the less insulated windows. I can not find research on the matter. I suppose another insight that I would enjoy would be the value of the R-40 double stud wall when combined with the R-2.5 windows. This is for RI, low Zone 5, and windows make up about 25 – 30% of the exterior wall. Thanks, Will
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