UK households could see their energy bills increase by as much as £145 in the New Year if they fail to switch to a better deal, research from gocompare.com has revealed.
The comparison website found that 13 fixed-term energy tariffs - including 10 from four of the UK's Big Six suppliers will be ending on New Year's Eve. If customers fail to switch, they will be put on their suppliers standard tariff, meaning an average bill hike of almost 8% or £78 a year.
EDF Energy, M&S Energy, Npower, Scottish Power and iSupplyEnergy all have tariffs that are ending on 31 December, while customers living in the Eastern distribution area - which incudes East Anglia and Greater London - and those on Scottish Power's Online Fixed Energy December tariff are set to see the biggest annual increase of £144.93 when they are switched to the supplier's standard tariff.
Other tariffs coming to an end include EDF's Energy Blue+ (which has an annual cost of £1,097 compared to the standard tariff of £1,163.60 - a rise of £66.19 or 6.3%), M&S Energy's Fixed Price December 14 (£1,081.33 to £1,186.27 - a £104.94 rise, or 9.7%) and Npower's Online Price Fix December 2014 (£1,127 to £1204.91 - a £7751 rise or 6.87%).
Jeremy Cryer, energy spokesperson at gocompare.com: "Despite a mild autumn, temperatures have really plummeted this week, and with colder weather forecast British households will be using more energy to heat their homes. As such, it's important that people make sure they are on the right gas and electricity tariffs so they can help reduce their big winter bills."
He added: "There are lots of good deals to be had right now, and they are certainly a far better option than any supplier's standard tariff. In fact, there are eight sub-£1,000 a year dual fuel tariffs available at the moment."