my bathroom fan does not perform as expected. i run it all the time during showers and it doesnt seem to exhaust well. the bathroom is always fogged over and wet- i put my hane up to it and 1 side actually feels like air is blowing back into the room..... the fan is vented out into the soffit- i know i know.... it turns down into the eave and butts the vented soffit and is caulked around the perimeter so not to allow it to leak into the attic-----
is there a formula to see if the fan is large enough first- then ideas?