I currently live in a brick 1900-1904 era city rowhome and was wondering if anyone knew of any options for insulation possiblities to lower heating/cooling costs. Has anyone ever done this before? My heating oil is currently budgeted at $70/month for a 12 month service contract for heating this coming winter, and I could possibly end up paying even more if oil prices are higher than contracted for or I use more oil that last year. I've thought about the idea of trying to insulate for a couple years now, but with all the exterior walls being solid brick with finishing plaster on the inside it was suggested to me that I fasten styrofoam sheeting and drywall to the inside of the walls, but it seems to me I would loose a fair bit of interior space doing that as I have 3 exterior walls on the first floor. There is also the possiblity that the first floor ceiling is open across the walkway between my house and the neighbors. All walls and ceilings are the original lathe/plaster, and the floors are currently wall-to wall carpet on all 3 floors and stairwells (installed by the previous owner). The only other issue I have is cost... Anything I have done will have to be on credit. Is it even worth it to try to do anything or should I just pay the bills and forget about it?