50 years of heating with wood! I moved the air in every economically possible way. I used several large wood stoves as standard to heat 6000m². keep feet. The other circulates in the house. If they are under the house, they are hardly audible. If possible, position them in the middle of the pipes when drawing air from a wood stove to moderate the air a bit. We monitor the temperature of the pipe. Round out the 8" metal air duct next to the fan and keep it under 155 F. These units are rated at 170 F. There is no better/cheaper/economical/affordable device than this. The temperature in the store evens out immediately. lots of air with good static pressure. We also stretch about 3 inches of the filter. Our electric bill was noticeably lower compared to the old 1hp 14" squirrel cage fan we used previously. And we have one that went out of balance. When I requested a refund, it was here 20 HOURS LATER. These folks have treated me very well THANK YOU SO MUCH.