I don't think we're on the same page here. I'm talking about using a tec fan with a portable propane heater instead of using batteries to run its internal fan, not using tec fans as a solution for all heat distribution requirements. You use tec fans with Mr Heater style propane burners and micro stoves as often used for winter camping. If you're running your buck stove in the living room and want to distribute the heat to the other end of the house, tec fans aren't going to do it.