Hmmmm, would the decreased heat really be noticeable? Ie., do they still get hot, just not "as hot" ? Or is it pretty significantly different?
I'd just hate to find out AFTER going through the effort and expense of stringing the wire for 220 (240? whatever it is) that it's a sort of "here's your nickle per month that you save! <pling!>" type situation.
One follow up question for you electricians, what gauge wire does a person need for 240? 8 gauge? 10 gauge? (Distance from panel to room is roughly 50' {including the distance to ceiling and back}, in case that info is necessary to make the determination..)