I do not know what this test will prove. If you do not have a fire how do you test the chimney flow ? No one is going to have the fan running 15 minutes before starting the fire the fan is only used after the fire is good and hot with plenty of draft going on. I tested mine by having the stove running with coals and a fresh load of wood maybe 1/2 hour in so the air was lowered. After turning on the fan I checked the flame and fire performance for about 2 hours and did not notice any noticeable difference. I even tried opening a window in the stove room to see if the fire increased but it did not. On a new air tight house this may have a noticeable difference, and or if the stove was in the basement. In my house the return air has a wide open staircase to return up through. All I know is it worked for me. I would love to move the cold air instead, but moving cold air up from the basement would not be replaced by warm air downstairs without actually blowing the warm air down. In the colder months I will likely put a fan at the bottom of the stairs blowing up to increase air flow.