fiberglass insulation for 12 oc

[Cabinet Monkey]

12” o.c. insulation is (was) available but it’s a special order item from a supplier.

Given the wait time an expense / min. order I usually end up making a plywood template and cut down 24” with a special insulation knife.

[anwalt2]

I was wondering about using a heat pump water heater in a heated space in the winter, can you feel if the area is colder ?     In the summer I can see it is good but what is the full year efficiency.  
  Roly

Yes, I believe the basement is colder with the heat pump water heater

[MstrCarpenter]

Best trick to cut 2' x 4' batts in half? Don't cut the bag! Well at least not at first. 

I use a machete sharpened with a coarse file to purposely leave small serrations (like a utility knife blade). After marking my cut line, I start at the sealed end of the bag and stab thru the top at an angle out the end. This leaves some plastic to keep the insulation compressed. I cut and slice my way to the other end where I have a helper hold (or tape) the bag closed as I finish. The bottom piece may not be cut all the way thru, but that's also where the bag is still intact so I can push a, slightly larger, bundle into a crawl space.

Another way to cut one or two at a time at any width is to use two 5' 1x8's with cleats on both ends and a slot in the middle. It's much faster with a helper to line up their end and stand on it. I still like my machete, but a utility knife will work.

[oscarMadison]

Have you got insulation between the joists on the band boards at the perimeter? It will help. Probably help more than you might expect. You loose a lot of heat there.

i did this and was surprised how much it helped.

Also a thumbs up on rockwool. I used roxul and loved it. Plus you get some soundproofing from it.