Ive been burning one week today with my new oslo. compared o the wood furnace i had, i have burnt approx 1/3 of a face cord. The furnace would have consummed over a face cord. Ive been warmer too especially in the morning. I loaded last night at 10 at 7 this morning I still had 300 on the top it was 72 in here and a good bed of coals to get going.