You'd need to do a heat loss analysis on the house. 1 BTU/hr = about 0.293 watts. So, if you needed 50K BTU/hr, that would be 14.65Kwh. Not sure how many BTU/term you'd get but you need to factor in the efficiency of the heating system - new high-efficiency ones are in the mid-90% range. Electric is basically 100% efficient. If they don't have natural gas available, it is a moot point unless you want to install propane or oil.
It really depends on where you live. Where I live, electric heat would bankrupt the average person, but where my parents live, it's not bad - it's cheaper than heating with gas (although they use a heat pump, which is more efficient than resistance heating except when it is really cold and they need that, too).
So, it isn't an easy answer, but the tradeoff can be calculated.