Did a search because I know this has been kicked around but came up empty. I have two vertical 300 gallon tanks that I will be framing 2.5 walls around (It's in a jog corner of basement) plus a top. They have the usual taps of 1.25 supply and return both boiler and load as well as drains and vents plus a temp and pressure gauge, aquastat and a pump. The basement walls already have 2" blue rigid foam panels. I will use 3" blue on the floors as best as possible around the tanks that sit up on solid concrete blocks. At 70 bucks a sheet for the 3" it seems silly to keep going that route. I'm now thinking Roxul or fiberglass but roxul can be bought in sheets being easy to work with, not sure of rigid FG but I hate to itch and work with it anyway. Obviously with all the plumbing going on I need to maintain some sort of easy access so having the wall panels be removable is necessary. That makes dumping a few bags of blown in a non-starter. Spray foaming closed cell is crazy expensive even for the DIY kits. I guess I'm asking if some of you have any better ideas? I'm kind of a neat freak and final looks do count.