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High fan watt draw measurements are most often a result of high Total External Static Pressure (TESP), which affects the performance of the blower motor. The measured TESP can be used to cross reference the manufacturer's blower performance table/fan chart found in the specifications for the installed equipment. If the static pressure is too high, then that will affect airflow and fan watt draw. The linked articles have information on how to measure TESP.
A PSC motor will use less energy as the static pressure rises, An ECM/Variable motor will ramp up to deliver the CFM, but draw more watts.
I have attached two hyperlinks to NCI articles on static pressure.