I'm new here, and read many posts. This is a great site. Very helpful. I really want to move to coal, but I (and my wife) are cautious about "over committing" to coal. We're in western CT, 3500 ft 2 story colonial with partial finished basement. Oil furnace and oil DHW. Furnace is 20 years old, oil DHW is new. I've considered putting stoker furnace in parallel, but I have only one chimney, and already put both oil burners to it. Could direct vent, but I honestly don't like the idea due to power failures. Also the extra furnace in series is going to be tight. I like the idea going to a boiler with a new air handler, and it (considering the KA-6) should handle the DHW, but in the summer, wouldn't it be less efficient than keeping the oil DHW? Is the KA-6 even insulated? I could power vent, but how much risk (beyond code) would I really take by putting 2 appliance, coal boiler and oil DHW up the same chimney?
Also, we travel often, and I'm sure I'll need oil back up. If I get that option, I’m sure we'll use it more than I would like. I've only seen one post with an estimate about efficiency of the KA-6 on oil. Does anyone have any actual experience with these units running on oil? Would there be another better boiler design than the KA6 for using oil, (Harmon, EFM, perhaps)?
Finally, going from furnace to boiler is going to be expensive. ~$5k for boiler, ~$2k for air handler, $?? for some help doing the duct work. Maybe I should just "half commit" and get a Koker or Alaska 140, put it in series, and jam all 3 appliances and ducting + a power vent in there? This keeps my oil furnace which I assume should be more efficient (on oil), but seems ugly. I like the opinions I see posted here, they seem very sound and reasonable, and any assistance with my situation is appreciated.