More than 90,000 households in the UK face a £200 increase in energy bills, according to research from comparethemarket.com.
The price comparison website has warned that 93,000 households will be automatically switched onto default tariffs in the last quarter of the year if they choose not to act.
Between October and December there are 130 fixed energy tariffs coming to an end, with a cost of £18.95 million hitting those households affected, the service said.
The research suggests that the biggest increases in energy costs will impact households whose tariffs end in November, where the average annual energy bill increase will be £209.
October saw the greatest number of customers affected, with nearly 60,000 households expected to have been moved on to the more expensive “default” tariffs if they did not switch, at a combined cost of more than £12 million.
Peter Earl, head of energy at comparethemarket.com, said: “Every month, thousands of people are moved unwittingly onto more expensive default tariffs which can come at a huge annual cost. The business model of most energy companies fundamentally punishes those that stay loyal to their provider.
“The easiest way to beat the system is to switch provider and save hundreds of pounds in the process.”
“In the past few weeks, the insurance industry has come under growing scrutiny around the loyalty penalties that consumers face and the model that relies on inertia.
“The same level of scrutiny should equally be applied to the energy market where the exact same approach is taken to the detriment of consumers.”
| Month | Total cost to consumers | Est. number of consumers affected | Average increase | Number of tariffs ending |
| October | £12,005,778 | 59,637 | £201.31 | 56 |
| November | £4,296,842 | 20,531 | £209.29 | 32 |
| December | £2,656,256 | 13,397 | £198.28 | 42 |