I will probably be installing a wood boiler over the course of the off-season (spring/summer). My house currently has an oil fired 144,800 BTU/Hr boiler providing HW to an indirect domestic HW tank and two hydro-air AHU's. This serves heat to a 2600s.f., 2 story 2.5 bath colonial with (I would say) moderate insulation values. I've been monitoring the oil boiler operation and degree loss on 32 degree nights. On average, the boiler kicks on twice an hour, the upstairs hydro-air unit operates once and the downstairs unit operates twice with temperature swings between 62-65 degrees. My first question is, if they rate a boiler at 144,800 BTU/Hr., does the output produce that heating capacity if in operation for a full hour? Additionally, would a lower rated wood boiler at 100,000 BTU be able to keep up demand/idle less? Or should I size the wood boiler to equal the capacity of the oil boiler and have it idle more frequently? If I opt to go with the 100,000 BTU boiler, does this mean my wood consumption would be greater?