Hi, I am working on my folks place which is a 1930s SE US home. Its rather big (nothing fancy though) and has always been a blackhole when it comes to active heating/cooling. The main reason is the windows, that i got, but a close runner up is the walls. The walls are not hollow, they consist of 3 layers, the outside panneling, a middle wood layer? (sorry, am a construction noob), and then an inside beaded wall panneling of sorts; no where to stuff some sort of insulation. For what its worth most of the wood in the house seems to be pine (regular, not heartwood). I thought I'd post here to see what my options are as I haven't been able to come up with the right search query in google to get a meaningful result. Any ideas, or thoughts (perhaps i am not quite asking the right questions), would really be appreciated!