You are right, but your heating system is probably cheaper (unless you have simple electric radiators). If you have a heat pump, it will generate about 3W of h

You are right, but your heating system is probably cheaper (unless you have simple electric radiators). If you have a heat pump, it will generate about 3W of heat from 1W of electricity, so it's 3 times more expensive to heat with standby devices that with your heat pump. If you heat with gas, it's much cheaper per kWh than electricity, but I'm not sure what the ratio is.