Jake,

My brother has a similar unit which is made by LMF (same design, just put together by a different company).  This is his third year with the furnace and has only had one problem (the motor that drives the auger failed this winter).

He has a newer house (built 1993) and it is well insulated.  It is a single story ranch with about 1100 square feet.  The furnace actually puts out too much heat for this size of a house and he shuts it down when the outside temps go above 50 degrees.  It averages about 1.5 bushel of corn per day.  He runs it about 150 days per year, so it uses 225 bushel per year.  $4 corn * 225 = $900  He was using propane to heat the house before and he typically used 800 gallon per year ($2.50 * 800 = $2000).