Price rises are imminent, and it means even without the heating on, your bills could soar.
Millions of energy customers have been urged to switch suppliers or at least tariffs to save up to more than £400 a year before the latest round of price hikes comes into effect.
Some nine million customers of the Big Six companies should switch to a better deal or end up overpaying by up to £434, Which? has warned.
The latest price hike by British Gas came into effect on May 29, increasing the bills of four million of its dual fuel standard tariff customers from £1,101 to £1,161 – 5.5% or £60 – on average per year.
The amount is £364 more than the cheapest deal on the market, but still only makes the British Gas standard tariff the fourth most expensive of the Big Six firms after npower, Scottish Power and SSE once all price rises have come into effect, the watchdog calculated.
SSE customers on its standard tariff will see the biggest price increase at an average £76 more per year.
The firm announced a 6.7% price rise this week to come into force on July 11, meaning customers will pay £1,196 per year on average.
Overall, npower customers will pay the most as its 5.5% price increase will mean customers on its standard tariff will pay £1,230 per year on average from June 17.
How much you stand to save
Which? said npower customers on its standard tariff could save up to £434 by switching to the cheapest deal on the market, Utility Point’s variable tariff at £797 per year, or £268 by switching to npower’s own cheapest tariff.
British Gas households who want to remain with the supplier could save £113 if they transferred from the standard tariff to the best deal available.
Scottish Power customers on its standard tariff will see their bills increase by an average of £63 a year under a 5.5% increase coming into effect on June 1, bringing its standard tariff to £1,211 on average per year.
The one million households on this deal will be paying £414 more than if they were on the cheapest deal on the market and £100 more than Scottish Power’s own cheapest tariff, the consumer group calculated.