Over half a million households need to act before a certain date or risk having their energy supply cut off.

Those needing to act are households with electricity meters that rely on the Radio Teleswitch Service (RTS) to set the rate of energy. This service charges them cheaper rates depending on the time of day. The devices, such as Economy 7 and other multi-rate energy tariffs, pick up the different energy rates through the RTS signal – this is broadcast alongside the long-wave channel for BBC Radio 4.

Some RTS electricity meters can also automatically turn heating and hot water systems on and off during certain hours. However, the service is being turned off. This means households with these meters will need to switch to a smart meter or risk being disconnected, as the meter will no longer function as intended.

Warnings have been issued as these meters could be left jammed on peak time electricity rates depending on when the RTS signal dies. This could lead to huge bill hikes for households affected by the switch-off. The exact date the RTS system will be switched off is Monday, June 30 2025, meaning households only have four months left to take action. Those affected will need to upgrade to a smart meter before this deadline. According to Energy UK, around 530,000 customers rely on RTS meters.

Smart meters are energy meters which display your gas and electricity usage in real-time so you can see exactly how much you’re spending on energy each day. They work by calculating energy usage based on automated readings which are sent to your energy provider every 30 minutes.

Plans for a switch-off have been in the works for years; however, they have been frequently pushed back in order to keep RTS energy meters working, with energy firms footing the bill for the service. Ofgem was forced to step in last year as suppliers had been initially slow at switching people over. At the time Ofgem published its plan, it said the rate at which people were being moved over previously meant it would take until 2028 before all RTS meters were upgraded.

In recent weeks, suppliers have been racing to transition customers to smart meters ahead of the looming deadline. At the end of January, Octopus Energy messaged thousands of customers asking them to switch to smart meters before the switch off. Over 65,000 E.ON Next customers are also being urged to come forward and get a smart meter installed.

In a previous statement on the issue, an Ofgem spokesperson said: “We expect suppliers to consider a range of innovative solutions to ensure their RTS customers get on to a metering and tariff arrangement appropriate for them. Smart meters are the best replacement for RTS meters – giving consumers more control of their energy usage and opening access to new money-saving tariffs – however, customers should speak to their supplier to understand the options that are available.”

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