Yanche wrote:A coal fired stoker boiler piped in parallel or series with your existing oil boiler would be the best option. It will also give you unlimited domestic hot water cheaper that any other fuel.
If you were satisfied with the heat distribution in your house when you heated with oil baseboard, the heat distribution will be the same with a coal boiler. If there are problems, now's the time to correct/improve/zone, etc. You will be happy with the comfort for years. Most of the smallest sized boilers will be adequate for your home. Which manufacturer will depend on your choice of features important to you and the cost. Good value will come from a refurbished boiler.
If your oil HW system heated your house before, why wouldn't that system do just as well fueled again with coal?
We moved into my house a year and a half ago. Straight colonial with a full basement, built in 1973, originally all-electric, with, count 'em, 23 electric baseboard zones.
Previous owner installed my stoker coal furnace in the late '80's, with direct ductwork only to the first floor rooms, with the exception of the over-garage space on the 2nd floor. One return duct (plus a laundry chute!) from the 2nd floor.
I was worried. But, with minimal throttle adjustments depending on the outside temps, the coal heat is so even that the whole house is comfortable: 68-70° on the first floor, 66-68° upstairs.
I'm pretty happy, heating a 3700' house for what I figure is no more than half price, even when you figure in the cost of the electric blower and circulation fan. In the current weather (lows around 20°, highs in the 30's), I burn 100-125#/day and generate 35-40# of ash every other day.
So, for straight colonial design (living space on the main floor, bedrooms up), heating the main floor during the day can warm the sleeping space enough, just by convection, for comfortable sleeping at night. I've come to the conclusion that this is the essence, and the genius, of the colonial design. Of course, if you don't heat during the daytime, it could be tough to get the second floor warm enough in the evening. In that case, you might want to pipe up the second floor, or the part(s) of it that don't warm up enough. Another alternative would be some strategic through-floor circulation venting. Some combination of these strategies should fairly readily solve your problems at a much lower cost than oil.