I tore down some 70s wood paneling in my front bedroom of a 1920 rowhouse and there is no insulation except for the plaster on top of brick. Someone told me just to put on sheet rock(the plaster looks pretty back) and others are saying to put up the 2x4 frame and batt it down. Problem is that I am going to lose 4" to do so..? Being I am in between 2 attached row house, is the efficiency gained outweigh losing 4" off the front wall? Also, I would have to re do the window framing not sure how to go about that as well. I know sheet rock is the easiest way to go, but I want to make sure I am doing the right thing for a home I plan to stay in for many years. Advice please before I move forward.
An inch of foam and a half inch of sheetrock might suit your space loss/window frame issues better and still be a lot better than no insulation at all. Just use longer screws into the brick, and perhaps some adhesive to reduce the number of screws you need (each screw is a heat leak.)
Being in an attached row house, the front and back walls and the roof are the main places you need/want/should have insulation, as they face the world, not your neighbors' interior spaces.