I have a Monarch Add-A-Furnace wood burner connected by ductwork to my Armstrong Air electric furnace. I use the wood burner when it gets really cold outside, but shut it down at night because I do not want to get up every two hours to add wood. When I shut it down there are usually a few glowing coals left in the fire box so I have left the manual outlet dampers in the open position. Also,this unit has its own inlet air duct which is always open. Should I be doing something different at night as this procedure seems like it will vent heated house air up the wood burner stack? What is the most cost effective way to operate this combined system? Wood is plentiful so does not enter into the operating cost equation. Any advice is appreciated.