There's no such thing as an inefficient way to turn electricity into heat. A light bulb, a television, a fan, a refrigerator, a speaker, a kettle are all going to turn all of their power into heat.
And given the climate in the UK for most of the year the excess heat means your heating needs to do a little bit less[1].
1. But probably net less efficient in that the majority of houses in the UK use gas for their heating and gas is cheaper than electricy kWh for kWh in the UK.
