100% sounds efficient, but if you're set on electric heating then it's pretty lousy compared to an electric heat-pump. For example, I have an aircon at home that runs at about 400-500% efficiency for heating - not unusual these days. Admittedly, though, it's not so easy to fit as a light bulb, and not so bright either!
I've got a heat pump and it's much more affordable in the winter than electric heating. My wife's previous apartment was the bottom floor of a converted old house with electric radiant panels in the ceiling. It was a terrible design, because if you were right under them, you'd feel a bit of warmth, but they didn't heat the house at all (well, probably the upstairs neighbors). Her 2-room apartment had a $350 / month electric bill in the winter, and she kept her thermostat at 50F. Now, we live in a 6-room house with a heat pump, and our electric bill is about $160 in the winter, with the thermostat at 68F.