Npower has become the fourth of the Big Six energy firms to announce a winter energy price rise in a further blow to households already suffering during the Big Freeze.
Millions of households faced with winter energy price hikes can use a little-known loophole to maintain existing costs, as long as they then switch supplier.
Almost two million Npower gas customers will receive refunds that will total a whopping £70 million, over three years after they were overcharged by the energy giant.