Thanks, I'll try the smoke thing. Actually there is no noise of wind at all with or without the door closed. I have to stand real close to the fan to hear a soft humming sound. The fan blades seem to move fast but to no effect! I also just realized something that might be linked to the operation of the fan. It works alright when I turn on the power from the switch outside the bathroom, although the suction is weak as I've mentioned above. But when I use the cord - the fan stops when I close the cover via the cord, but no matter how i pull it again, the cover doesn't open. I have to use my fingers to push the cover open. Is this how it works? I notice little knots on the cord, do the knots affect the operation of fan? Sorry, hope you guys understand my description. Appreciate any advice, pls. Btw, I left a msg for KDK, but they are on company retreat till 27th.