in my garage conversion, the studs in the two inner walls -- i.e. walls between the outside two bays of the garage -- are about 24" apart. i was planning on using r13 insulation batts but come to find out that in my area literally no one has r13 in that size, nor can they get it. it's 15" or nothing for the 2x4s. so:
how much insulating power am i giving up by going to r11, which i can get in the right width? remember: these are inner walls; but the space on either side is unheated.
or maybe i could get the 15" stuff and use 1 1/2 batts per opening?
or i could add more studs.
what do you think?