I won't be a complete pig over this; I won't switch on every fan heater I've got, but were I to do so, that would spend less than £1 to severely overheat this small well-insulated ordinary house.
What I will do is switch on the small wall-mounted heat pump to draw 0.7kW and deliver about 2kW of heat, both for half of the time. Expected cost is much less than £0.10 for expected gain of several kWh of heat to one room overnight.
The cause of this overnight electricity glut is likely to be a lot more wind than average, so those who can use it should.
This kind of bargain does not often happen. This time-of-use pricing deal won't suit everyone because it is extra-expensive at after-school time 4pm-7pm, recently going over 40p/kWh. I just don't use much at those times, and preferentially use the cooker and heavy appliances at less expensive times. Daytime <20p/kWh and occasionally much cheaper is available to those who bother to use it.
Last edited by wizzo227; 12-10-24 at 19:26.