tvb wrote:You guys realize you didn't give the answer I was hoping for - that heating with steam + coal was not possible!
In any case, how is the efficiency of said steam units?
As it is now, the boiler rarely comes on with us using the VC Vigilant. Early mornings tend to trip it on because the ash buildup cools the stove and I expect that will end with the installation of the new Harman mag stoker. Would doing both be worthwhile or simply redundant?
I had steam heat when I was a kid, thinking back it was kind of neat. And it was hot!
A coal fired steam boiler is up there, 85%+. They are efficient (and cheap to run on coal). One issue is that it provides no heat until it has built up a enough pressure. That shouldn't really be a problem, you just need to wait. They have a little more control features (level, low water cutoff, etc.) to them and will require blow downs on occasion. The valve stems, sight glasses and a few other things will tend to need "fettling" over the years. The beauty of hot water is that it reduces the maintenance issues to the system.
To help in your decision, the boiler is going to have about a 15% efficiency edge on the stove. Your home will be evenly heated. Every hour your oil burner is off, saves you about $3.XX. You empty the ash every 3-5 days. With a bin and feeder, you never touch the coal.
Does this help?
In your case, yes, it would be redundant to have both a boiler and stove. If you want very reliable steady cheap heat with very few trips to tend it, a stoker steam boiler will do that very well.
If you don't mind the fire going out, the oil burner firing and playing with ash in the house every day, just keep the stove.