I have 3 weeks to kill before my new flooring shows up, so looking to tackle the front room. It's framed with rough sawn 2x4's, so I plan on furring it out to accomadate at least R-19 (current is R-11 with no vapor barrier. Like living in a barn.) Lineal footage is 57' along the walls and an 8' ceiling. Plus, huge old dbl. pane windows I won't be able to replace for a while. The attic space above it will get an additional R-38 of blown in after this is finished, as will the rest of the attic space (40 bags) So, is the R-21 worth it? thanks, JB EDIT- Sorry, should have asked if the cost difference between R-19 and R-21 is worth it. For my situation, I don't think so, but that's why I'm asking. R-19 is about $0.51 per sq./ft R-21 is about $0.74 per sq/ft. The diff. is about $100.