Household energy bills are set to rise by 0.2% from January 1 after Ofgem increased its next price cap. The regulator said energy bills will rise by about 28p a month for the average dual-fuel household in England, Scotland and Wales.
You can use our gadget below to work out how much more you'll be paying. The increase amounts to an average overall bill of £1,758 per year for those on a default tariff, up from the current £1,755.
The unexpected increase comes after experts at Cornwall Insight said they expected prices to fall by 1% because of lower wholesale energy prices.
Ofgem said wholesale prices were currently stable and had fallen by 4% over the past three months, but that conditions remained "volatile".
Tim Jarvis, director general of markets for Ofgem, said: "While energy prices have fallen in real terms over the past two years, we know people may not be feeling it in their pockets.
"The price cap helps protect households from overpaying for energy. But it's only a safety net and there are practical ways that customers can pay less for their energy.
Use our gadget below to work out your new monthly bills:
"While wholesale energy costs are stabilising, they still make up the largest portion of our bills which leaves us open to volatile prices."
Energy consumers minister Martin McCluskey said: "We know that energy bills remain too high. That is why we are taking immediate action, with millions more families receiving £150 off their bills through the expanded warm home discount scheme this winter.
"We are taking the long-term action needed to bring down bills for good with the Government's clean power mission.
"We are also delivering our new golden age of nuclear, with cheaper, clean electricity to power millions of homes, kick-start economic growth and create thousands of jobs."
Shadow energy secretary Claire Coutinho said: "Ed Miliband promised to cut everyone's energy bills by £300 but more and more experts are sounding the alarm that his plans will lock us into paying higher bills for decades.
"Despite gas prices falling, independent experts, energy suppliers and academics say it's the extra costs of Ed's net zero targets that are putting upward pressure on bills.
"This week we had a report that green levies on bills will soar by another £260 by 2030. We simply cannot afford this - cheap energy has to come first."