I'm trying to figure out if electric heaters could be used to replace oil heat in my situation. The upstairs doesn't quite get warm enough, so the oil boiler is run for the upstairs zone in the evenings for 4 hours or so. I figured that even running 2 1500 watt heaters flat out, which won't happen since the two rooms are already at 64F or so, I'd use the equivalent of .3 gallons of oil a day. Based on my previos calcs w.r.t. dhw use, I figure in 2011 I used between .5 and .3 gallons a day of oil, so I should do better. I'm thinking I might also have a happier "customer" as well. If it works out, perhaps some heat pumps could be in the cards, but you can't beat the initial price of a portable electric resistance heater. I realize my numbers are fuzzy. Does anyone have some real world experience? Thanks.