It might be due to where you are, propane is one of the most expensive options in my area. Cost per million BTUs as a point of reference, propane is like three times more expensive than my electricity usage even if I were using coil heaters, which I'm not. I use propane out in the barn and just the heat a 20wx20lx10h insulated loft for the weekend costs about as much as heating the entire house for the month.