I am looking for suggestions about how to upgrade a home that has recessed wall radiators.  I have seen mini-splits put in old houses with stand alone hot water radiators (that don’t interfere with the wall cavity).  That seems to work for all but the coldest days here in Massachusetts.  But now I am looking at a house built in 1952 with radiators built into the walls.  The metal must conduct the cold and there isn’t much room for insulation in the walls behind them (if any!).  I’m dreading the cost of having this heating system taken out completely.  Burying them in spray foam might be easier, but without taking the radiators out, I imagine the efficacy would be greatly reduced.  Has anyone done this before?  Are there any cost saving fixes that don’t involve cutting out radiators and patching the walls with insulation in every room?  Thanks!