I am going to insulate my knee wall myself. The NY Energy Smart audit suggested insulating the knee wall saying it would save about $75 a year. The consultant listed a cost of $840 to do it. I can do it myself for much less. They recommend insulating it to R16. I went to Home Depot and found R13 and R19, but no R16 batting. Hmmm. But after some research I found that what I want to do is place R13 batting in between the studs. Caulk the vapor barrier to the studs, and staple every 10 inches or so. After I cover the wall, I will cover all of the batting with rigid foam insulation caulking it in place. I think I can do it all at a cost of under $100. I saw the rolls of R-13 batting for about $11 at Home Depot, and I think I only need 4 or 5 of them. I didn’t look at the rigid foam, but will check tomorrow. Maybe I will stop at Lowes at lunch time. According to the audit report, I have about 210 square feet to do. The audit report says ’3.5″ Fiberglass,1″ XPS Siding, R-16′. So I am assuming I am reading it right.