I am thinking about replacing my current pellet stove with a natural gas fueled free standing direct vent stove. I am trying to calculate the average cost of operation (per hour) of the natural gas stove to see if its less expensive than the pellet operation and should I proceed with buying the natural gas stove. The stove I am looking at is rated at 16,000 to 32,000 BTU's. My question revolves around how will the stove operate, at what average BTU will the stove produce after it brings the zone to the preset thermostat temperature. In other words will the stove operate at 10,000 BTU's + or- X BTU's as I realize it won't be pumping out 32,000 BTU's constantly. All the formulas I find tell me to enter the max rated BTU's for calculation. Is there a "average" BTU I can use in my calculation or calculate it out at max BTU and smile when I read my gas bill when its lower than I figured.