That depends on what the source of your heating is.

Say, in Norway we largely use (hydro-) electric power for heating, anyway.

So, the 2% efficient (for lighting) incandescent bulb doubles as a 98% efficient space heater, utilizing the 2% loss to light said space. 100% efficient!

No, since the domestic heating is done mostly by heat pump, which is above 250% efficient by comparison.