Unlike oil, gas, coal or wood, electricity does not emit CO2 when converted into heat. Its production method can be polluting, however.

Electric heating: more or less polluting than oil-fired heating?

It all depends on how the electricity is generated:

• a traditional oil-fired power plant consumes about 2.5 times more fuel to generate the electricity needed to produce 10,000 kWh of heat than a refinery consumes to produce the amount of oil to achieve equivalent heat.
• gas-fired power plants have better output but are less fuel-efficient  than the production of the oil needed to achieve equivalent heat.
• if you heat your home with electricity generated by renewable production methods (your solar panels, for example), there is no pollution.

Electric heating: more or less polluting than gas-fired heating?

The output from gas-fired boilers, especially condensation boilers, is still better than from oil-fired boilers. They are normally far less polluting than electric heating unless you are using renewable electricity for your heating.

Electric heat pumps: three times less polluting than electric radiators

Lastly, if you are thinking about electric heating, it is far more cost-effective to invest in an electric heat pump than in electric radiators.
Heat pumps consume three times less and therefore pollute three times less for the same amount of heat produced.