Used for 2 winters now in Zone 5 and we go through only about 2 cords to heat 2000sqft. After packing for night the house never dropped below 65F when we woke in the morning. We just had chimney swept and it produced about a pint of carbon and our wood is all a mix of piñon and juniper. Favorite part - never get smoke or soot floating out when we open door to feed the fire. It is the cleanest stove we've ever had.