I first heated with the same style electric heater in the above post and still have for a backup. It is however extremely expensive to operate here in New England.
My pellet stove goes thru roughly 2 1/2 tons per year and my Garage is 24X26 and two stories. So it costs roughly $800 for the year to heat.
My monthly Electric bill in the winter when using the electric heater in Garage was anywhere from $350 to $400.
The heater depending on temps would easily add $150 to $200 per month to the bill.
Electric is not the way to go in New England in my opinion.
Marc