An electric heater is inefficient if the electricity was generated inefficiently.
Inefficient: burn methane at a central point running a steam engine generator, dumping tons of waste steam into the air, run the electricity to your house and turn it into heat there.
Efficient: pump methane to your house and burn it there.
More efficient: burn the methane at a central location running a steam engine generator, carry both the steam and the electricity to your house, heating it and running appliances.
The moral: live densely enough that steam pipes are practical.
Inefficient: burn methane at a central point running a steam engine generator, dumping tons of waste steam into the air, run the electricity to your house and turn it into heat there.
Efficient: pump methane to your house and burn it there.
More efficient: burn the methane at a central location running a steam engine generator, carry both the steam and the electricity to your house, heating it and running appliances.
The moral: live densely enough that steam pipes are practical.