Gas and electric customers are being warned that a rise in energy bills could outpace inflation next year.
The Office for Budget Responsibility (OBR) is predicting above inflation price hikes in the new year which will pile further pressure on households already scraping by due to ever-increasing energy bills.
Chairman of the OBR, Robert Chote, warned that prices would be 'bigger than normal' next year.
In an updated official forecast for the UK economy, the OBR warned that the upward trend on household energy prices was likely to continue long-term.
The report stated: "Some UK energy suppliers have pointed to increased distribution, network and environmental policy costs as well as wholesale energy cost pressures.
"These network and environmental policy costs may persist in coming years, suggesting that further rises in retail gas and electricity prices may be likely in future."
As much as Â£70 could be added to the average household energy if there was a further rise of five per cent, a rise which would bring the average annual bill to around Â£1,420.
However, at present the OBR has not put a definitive figure on price rises into its economic model.
With E.On recently confirming that it will be rising its prices in the new year, all of the 'Big Six' energy firms - all part of the Warm Home Discount Scheme - have now bumped up energy prices this year. This increase has ranged between six per cent and 11% depending upon the provider.
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Latest supplier prices change: 27 July 2015Price updates