npower changed their tariffs for off-gas grid electricity customers following an investigation by industry regulator Ofgem, which claimed that existing customers had not benefited from dual fuel discounts offered to other consumers by the energy firm.
Commenting on the firms pricing policies, Kevin Miles, chief executive officer of npower retail, said the price of wholesale gas has reduced but remains "nearly twice as expensive as it was two years ago".
He added: "If we see a significant decrease in wholesale prices across the winter and this is sustained, then we will be keen to reduce our prices."
Richard Haddelsey, from energy analysts McKinnon & Clarke, recently told the Daily Mail that UK utility companies are slower to pass on wholesale reduction in gas and electricity prices to consumers than others across Europe.
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.