Millions of British households are unknowingly sitting on cash they could reclaim simply by checking their energy accounts.
According to Ofgem, energy suppliers are currently holding more than £3billion belonging to their customers.
For the approximately 17million homes paying through fixed direct debit arrangements, this translates to an average credit balance of £212 per household.
This figure has increased from £206 at the same point last year.
With warmer weather now reducing gas and electricity consumption to its lowest levels, this represents an opportune moment for customers to review their accounts and potentially request refunds on any surplus funds.
The accumulation of credit occurs due to the structure of fixed direct debit payments.
Energy companies estimate a household's annual costs and divide this sum into twelve identical monthly instalments.
Consequently, customers pay roughly equivalent amounts in summer as they do during winter, despite using considerably less gas and electricity when temperatures rise.
This arrangement means credit steadily builds up in accounts throughout spring and the warmer months.
Maintaining some credit is beneficial, as it provides a cushion against higher winter bills.
Experts suggest retaining approximately two months' worth of payments as an appropriate buffer.
British Gas maintains a £75 credit on active accounts
| GETTYAny amount exceeding this threshold could potentially be claimed back as a refund.
Ben Gallizzi, energy expert at Uswitch, said: "More than half of UK households are coming out of the coldest time of year with credit in their energy accounts."
He noted that households would typically have depleted most of their credit during the colder winter period.
"However, it is advisable to keep about two months' worth of payments in energy credit to cover higher winter bills ahead," Mr Gallizzi added.
Energy bills to rise by £209 in July as Ofgem price cap expected to hit £1,850 | GETTYWith energy prices set to increase in July, he suggested that customers holding more than two months' credit might consider leaving some funds with their supplier to help offset the impact of higher bills later in the year.
To request a refund, customers should first ensure their supplier has current meter readings on file.
If readings are inaccurate, monthly payments may need adjusting before any refund can be processed.
Once meter readings are confirmed, anyone in credit for more than a month has the right to request their money back.
Millions of households could be paying more without even knowing | GETTYEach supplier operates differently when processing refunds.
British Gas maintains a £75 credit on active accounts and will only return funds if at least £5 remains above this amount, with requests made through online accounts.
OVO Energy permits refund applications when credit exceeds one month's direct debit by £25 or more.
Customers whose requests are declined can challenge their bills.