Low income and vulnerable families could face higher bills and issues with their heating and hot water amid the imminent phase out of older style electric meters.

RTS meters were introduced in the 1980s and use outdated radio signals to switch between peak and off-peak rates. The process to turn them off is due to start on June 30, 2025.

Dwyfor Meirionnydd MP Liz Saville Roberts has called on the UK government to delay the shut-down of radio tele switch meters (RTS) until all affected households are fitted with alternative meters.

Data from Ofgem shows there are approximately 790 RTS meters still being used in Dwyfor Meirionnydd, with around 11,000 still in use across Wales.

They were designed to help households using electricity for heating and hot water, including electric storage systems, panel heaters or water tank immersion heaters.

Ms Saville Roberts says if they are not replaced, some heating and hot water systems could stay on all the time, not come on at all, charge at the wrong time, or turn on and off at odd times.

She raised the matter in Westminster during a debate on broadband and connectivity.

Calling for the switch off to be paused, she asked what could done to help the 11,000 affected households, including vulnerable people and those living off grid in rural areas dependent on the system.

The Minister for Science, Innovation and Technology Chris Bryant asked her to write to him, so he could pass the matter to the Department of Energy, Security and Net Zero.

“She makes a totally legitimate point , we have to make sure we get that right,” he said

Liz Saville Roberts MP said: “With just over a month until the switch-off, I remain concerned that nearly eight hundred households in Dwyfor Meirionnydd are still using outdated RTS meters and have not yet been transferred to smart meters or alternative options.

“It is vital that energy suppliers redouble efforts to get these households connected to a replacement system.

“There is a real risk that those in our more rural areas will be left without heating and hot water, or face problems with their energy bills.”

Many people may not realise that they’re on an energy tariff that uses RTF, especially in rural areas where electric storage heating is common.

The MP added: “If people are not aware of the switch-over they won’t act, leaving them open to problems.

“I am concerned that electricity suppliers may not be able to transfer people onto smart meters in time or – more worryingly in my constituency – not be able to install a smart meter because of a lack of signal.”

Head of National Energy Action Cymru Ben Saltmarsh said: “When the Radio Teleswitch Service starts being switched off from the end of June, any meters relying on it could begin to lose functionality.

“Anyone who thinks they may have one should get in touch with their supplier to talk about upgrading to a new meter as soon as possible.”