Was just installed by my landlord in a small, early 1900's duplex of 1,100 sf, two story, unfinished drafty basement, insulated attic, no insulation in the walls, ten large, cheap, older vinyl replacement windows with no additional storms, in Newton, MA just outside Boston. Just did the radiator calculation and have roughly 213 sf. of cast iron radiators in one zone plus the 45 gal Super Stor on its own zone. Boiler was piped just like the instruction manual indicates, with a primary and secondary loop (even though it's only one zone of heat). What can be done to maximize efficiency given the too big boiler? I realize there will be a short cycling problem on the heat loop. We have the outside temp sensor hooked up. I can't install a buffer tank because I don't own the place. Have not used the heat yet.