An urgent alert has been issued to thousands of households who are still using old meters. The warning comes ahead of a major change that is likely to be implemented from the next month. 

According to the energy regulator, Ofgem, the 40-year-old Radio Teleswitch Service (RTS) will come to an end on June. This means the radio signal that controls them will be switched off - with a risk that customers could be left without heating and hot water. Data shared by the Energy UK has revealed that 430,000 households that were still using RTS meters by the end of March. 

An Ofgem spokesman told This Is Money: “The RTS upgrade programme is an urgent consumer welfare issue and Ofgem is determined to explore every avenue to ensure that customers are protected when this ageing 40-year-old technology is phased out from 30 June 2025.”

According to the suppliers, they are struggling to switch enough customers ahead of the deadline.

With the deadline approaching, the regulator is reportedly working on a backup plan for the customers with RTS meters in case the meters are not replaced by June 30. 

The energy regulator Ofgem previously told This Is Money it expected to transfer 100,000 customers using RTS every month until it is switched off.

Energy UK said more than 1,000 RTS meters were being replaced each day, but it would need to do five times more to reach the target. The regulator did not say whether it would fine suppliers or postpone the switch-off date again.

An Ofgem spokesman told the publication: "Ofgem set up a taskforce alongside Energy UK, bringing together suppliers and the wider sector to accelerate the rate of meter upgrades to its highest level yet, and solve complex technical barriers posed in certain remote regions.

"In recent weeks we have seen evidence of suppliers significantly stepping up their activity in these remote areas, such as the Highlands and Islands of Scotland, and solutions to improve smart meter connectivity in the north have been launched. So we urge any customers who may have previously struggled to get their RTS meter replaced to please contact their supplier again to arrange an appointment.

"Ofgem has also demanded action plans from every supplier, which we are scrutinising on an ongoing basis to ensure that robust contingencies are in place to protect any customers who remain on RTS meters after the phased switch-off process begins."