Quote Originally Posted by Graywolf
The best way that I have found without information, is to just measure static pressure, which is easy to do with a length of clear plastic tubing. If you drill a hole in the duct and attach a length of clear hose to it, it is possible to loop it around so that it makes a vertical ā??Uā?, add water to the hose, and see how much higher it lifts the water in one leg vis a vis the other.
Agreed, the details of the fan involved are important. Wouldn't the diameter of the clear hose be a factor? If the diameter were a quarter inch it would take less pressure to lift the water than if the diameter were say 3". Regardless, my comments still stands. In general terms, a large fan dialed down will produce less noise than a small fan running at top speed. And again, increasing the diameter of the downstream duct will also greatly reduce noise.