More families are in debt to their energy supplier, with one in five UK households owing money, a study said today.

Collectively, Britons are estimated to owe £637 million to energy firms, which is £159 million more than last year's projections, comparison website uSwitch found (see our Cheap Energy Guide for help getting the best deal).

Some 20% of bill payers surveyed by uSwitch, equating to more than five million households nationally, are in debt to their energy supplier. Reasons could include falling behind with payments, as well as discrepancies between their estimated bill and the actual amount. This figure is up from 14% last year.

Just over a fifth of those in debt to their supplier said they were turning a blind eye to what they owe in the hope that the amount will go down naturally over time.

A similar proportion plan to pay off a big lump sum, while one in 12 people in debt said they would need to agree a repayment plan with their supplier.

A recent string of price hikes by energy companies combined with the unseasonably chilly weather means the size of people's energy debts could shoot back up again.

According to the report, the average annual household energy bill now stands at £1,353 a year, up almost £100 compared with a year ago.

Regular meter readings

uSwitch says people can cut down on energy costs by paying by direct debit as suppliers tend to offer discounts for paying in this way.

Consumers should also make sure that someone is taking regular meter readings, as relying on estimated bills can be a "shortcut to debt".

For help getting the cheapest energy tariff for your needs, see's free Cheap Energy Club.