Consumers are set to pay, on average, an estimated £333 more for their energy over the next year if they roll over on to a standard tariff, as 70 fixed price tariffs come to an end in Q2 2017, equating to nearly a whopping £200m “inertia windfall” for energy companies.

comparethemarket.com’s data shows that there are 30 fixed tariffs ending in April alone creating an average annual increase of £359 per consumer if they roll onto a standard variable tariff. This increase is estimated to affect around 600,000 people nationwide.

The majority of the tariffs ending are from smaller, challenger providers, with only 23 coming from the Big Six. However, this still accounts for almost 200,000 customers.

Total cost to consumers Average increase Number of tariffs ending
April £102,170,015 283,944 £359.82 30
May £45,169,089 143,900 £313.89 18
June £51,334,538 168,411 £304.82 22
Q2 Total £198,673,643 596,256 £333.20 70

Commenting on the data, Peter Earl, Head of Energy, comparethemarket.com, said: “The cost of not actively monitoring your energy bills is clearer than ever, with energy companies potentially enjoying close to a £200 million inertia windfall from customers who don’t choose to switch. A £333 increase in annual energy bills could be devastating to so many families across the UK. However, the good news is that this can be avoided – by switching back on to a competitively priced fixed tariff which best suits your needs.”