Wood/coal boiler came online in November. Have installed barometric damper to get more heat out of it, and longer burn times. Got both.
From November 11 to December 18, I burned 77 gallons of oil... 3,500 sf, three unit, apartment building, with the basement (75 sf) set at 68 degrees. During the REALLY cold times, I burn the airtight insert in the living room fireplace in my unit. Gives me longer burn times on the wood/coal. House is rated at 130K btu for heat loss, wood/coal boiler is rated at 90K btu, and the insert?? God knows... darned hot. Drive you right out of the 1,700 sf I occupy. Would have stuck with it and not done the wood/coal boiler, but I was already spending 17,000 dollars on a new heating system. Spend another 5 grand and shove the oil man off into the corner... duh.
Seamless transition between the two boilers the way it's set up. Wood/coal circulator comes on at 140 degrees when you light it, shuts off at 140 degrees when it goes out. Have aquastat on supply of wood/coal boiler that is a 5-6 interrupt... set at 140 degrees. Had to play with that a little bit to get it "just right". It is now...
High low on the combustion fan is 185 degrees with a 20 degrees differential. Overheat zone is set at 195, rarely comes on unless... hasn't come on lately.
No January oil delivery yet... not sure they're coming. I'll find a bill stuck in the door and it's going to be just like Christmas. Haven't burned 1/4 tank (275 gallons) according to the gauge, which reads a little low anyway. Anxious to the the "K-factor"... kind of like "miles per gallon" for your furnace.
Lined my folk's chimney a year ago, and replaced their slammer with a "Heatilator" EPA compliant insert, afterburner model... they had oil delivered last week for the first time since last spring. They burned 33 gallons... my father was so happy he was nearly in tears.