Today you have a bunch of different routes you can take.If you plan on doing it yourself this pretty much the only way you'll save money,unless you plan on changing out your unit.
There are a bunch of Supply house's on the North Shore but the first one to mind is SG.Torrice CO.80 Industrial Way Wilmington, MA.
You'll need to buy a stapler and foil tape and most importantly mask's don't F with this stuff
I found this quick on You Boob thought it should give you a pretty good idea.
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