Ah, but was the furnace properly sized?
What is the insulation value of your walls and ceiling? Windows leaky? Do you have a 2 pipe vent system or just the exhaust?
How warm do you keep it inside?
If your ductwork is bad for airflow, that ECM motor will attempt to deliver the CFM the board is demanding through the feedback loop... resulting in higher amp draw and no savings compared to a PSC motor.
Look at your electric bills during the months with no furnace or AC usage to establish a rough baseline. A good part of the difference between that timeframe and winter is the cost to run the blower motor.