British Gas has increased its tariff while EDF Energy puts the freeze on for its customers this winter.
British Gas has announced domestic tariff increases for gas and electricity in the same week EDF Energy announced it a winter price freeze guarantee.
EDF Energy will freeze its standard energy prices at least until early March 2011. According to the company, on average, it will be "up to £70 below the level of Scottish and Southern Energy's dual fuel prices when its 9.4% gas price rise comes into effect on 1 December".
EDF's director of residential customers, Jim Poole, said: "We know these are difficult times. With people using over six times more gas in winter than in summer, any help we can provide at this time of year goes a long way."
Meanwhile, British Gas has informed its customers that it will increase tariffs by an average of 7% from 10 December 2010.
This will amount to a rise of £1.50 on the average weekly dual fuel bill, says the company, affecting around 8 million customers on its standard and variable tariffs.
The price rise will not be applied to British Gas' "300,000 most vulnerable customers", such as "the poorest pensioners" until after winter.
British Gas managing director Phil Bentley said: "We know that rising energy prices come at a difficult time for many in Britain. That's why we are not raising prices for our vulnerable customers until after this winter."
The company's 1.6 million customers on fixed price deals will not be affected by the changes.