The experts warn that your energy bills could be set to increase by as much as £214, as three super-cheap price guarantee plans are set to come to an end in the next two months.
So who will it affect, and what can they do?
The hikesThe three super-cheap plans cost £1,064 a year on average and start to run out at the end of March: they are EDF Energy's Fix to March 2013 and npower's Go Fix 10 and 11.
These deals were bought in December 2011, protecting buyers from all the hikes in the interim. However, according to uSwitch, if people on these plans allow themselves to be simply shifted onto their provider's standard deal, they will see average bills of £1,255 a year - £191 or 18% more.
In the worst case scenario customers could see their bills go up by £214 as their fixed price ends. The cheapest of the three, npower's Go Fix 11, ends 21 May. It costs £1,033 a year on average. This is £214 cheaper than the plan that npower is rolling customers onto.
Thomas Lyon, energy expert at uSwitch.com, says: "Fixed price energy plans are designed to protect consumers from price hikes. The fact that so many people will be seeing their energy bills go up as their current fixed price deal comes to an end means that these plans have been doing their job."
What can you do?If consumers want to take the sting out of the move, they will need to shop around for an alternative. They can save some cash by ensuring they are with their current provider's cheapest deal. The npower customers, for example, can save an average of £63 a year by switching to the company's cheapest deal.
Alternatively, they may still want to fix, in which case uSwitch says that the cheapest fixed price tariff is Ovo's New Energy Fixed, which fixes prices for 12 months from going live and costs £1,172 a year on average. They would still pay more, but would be protected for a year.
If they want a freeze for longer, the site says it's worth considering EDF Energy's Blue + Price Promise June 2014, which costs £1,182 a year on average, and is fixed until the end of June next year. This deal doesn't have exit penalties either - so if prices fall you can switch to a more competitive deal.
The fix questionFor those wanting even more certainty, there's npower's Price Fix December 2015, which fixes the price at an average of £1,305 a year, and is the longest fix on the market. It's worth being aware that this is substantially more expensive than the cheapest deals on the market, so will be for those who think energy prices are set to keep on rising for ever.
There are plenty of people paying the price for having fixed at the wrong time. The good news for many of them is that they will actually see their costs go down in the next month. One plan that backfired was the British Gas Fixed Price March 2013, which was sold in July 2011 and typically costs £1,307 a year. This is an average of £34 a year more expensive than British Gas' current standard direct debit price.
Lyon recommends: "For those who prefer the security of a fixed price plan, see what your current supplier can offer, but then compare with other fixed price plans on the market to find the most competitive deal. It's also important to be aware that most, but not all, fixed price plans carry an early exit fee - consumers should always check the small print carefully and ensure that an energy plan meets their needs before signing on the dotted line."