The Ecofan is advanced technology in which the fan is powered off the heat of your stove, no electricity for this product. The fan has to be positioned on the back corner of the stove in order to pull the warm air and push it to the center of the room. The fan cannot be put in the center or the front of the stove because otherwise it will overheat and void the warranty. The 800 Ecofan is the smallest version. The 802 Ecofan is the larger version and the 806 Ecofan is designed for a gas application.