I have an Ashley brand wood furnace,I have mine tied in the duct work and I heat the house basement and all (2800 sq ft total) easily.I have a wall thermostat that kicks the combustion air blower on when the temperature falls below set point (which does not happen very often) the house is kept at 75 degrees,even on the coldest night,10-15 below zero,I have a wheelbarrow and I burn from 1 to 2 loads a day.This thing paid for itself the 1st winter,which makes me think,I need to start to work on the woodpile.