I would say at least 1/2 the basement is finished. From what I can see, from looking at the non-finished areas, the finished areas are not insulated at all. You can see the studs and drywall.

What I'd like to do is put some insulation in the walls to retain some of the heat in this finished area--tends to get a bit chilly.

How can I do this without having to tear down the walls? Is it even worth the effort? Foundation is poured concrete.