More than half a million British homes have been warned they must switch to smart meters in the next five months or risk paying higher bills.

The warning from energy regulator Ofgem urges owners of the old radio teleswitch service (RTS) electricity meters to accept the offer of a meter upgrade from their energy supplier before the RTS service is turned off at the end of June.

The campaign is supported by trade association Energy UK and consumer groups National Energy Action (NEA) and Energy Action Scotland (EAS).

The campaign is running across TV, video on demand, radio, digital audio, billboards and local press, highlighting the urgent need for RTS users to book the installation of a new meter as soon as their energy supplier contacts them.

Failure to act may result in the heating and/or hot water being continually left on or off, or the charging-up happening at the wrong time of day, leading to higher bills.

Last year a taskforce was set up by the industry in recognition of the scale and significance of the task. It has been coordinating a range of activities and is committed to increasing the pace and number of RTS upgrades.

RTS meters are older electricity meters that use radio signals to switch between peak and off-peak rates. RTS was introduced in the 1980s and has reached the end of its natural operational life. The radio signal and supporting infrastructure and systems will be shut down from 30 June 2025.

The RTS taskforce includes Ofgem, Energy UK, energy suppliers, district network operators, Smart Energy GB, government and consumer groups. Taskforce members have signed up to the RTS Call to Action, a commitment to work together to replace RTS meters across Great Britain.

The taskforce (www.ofgem.gov.uk/publications/radio-teleswitch-service-rts-taskforce) is coordinating activity in areas with the highest number of RTS users, including working with stakeholders to raise awareness of this issue among affected homes and businesses. It is devoting extra engineer resources, fast tracking RTS meter upgrades and prioritising those in vulnerable circumstances. It is also tackling technical difficulties and sharing knowledge and expertise.

Fuel poverty charities NEA and EAS are also supporting the campaign. The taskforce is helping NEA and EAS’s local partners understand how the RTS switch off could affect their community members, so they can respond to enquiries and encourage affected households and businesses to take action.

“This new high-profile campaign is a welcome step forward which we hope will enhance the hard work already being done to reach out to affected customers and encourage them to make appointments,” said Charlotte Friel, director at Ofgem. “This kind of collaborative working epitomises why we set up the RTS taskforce alongside Energy UK, bringing together suppliers and the wider sector to accelerate progress.”

Dhara Vyas, CEO of Energy UK, added: “Energy suppliers are working closely with consumer groups and the regulator Ofgem to urge customers with RTS meters to act now to upgrade their meter. Energy suppliers continue to make every effort to get in touch with customers to ensure they have a swift and seamless upgrade, and can give extra support to households that need it. By making sure they are in contact now, customers can minimise disruption, arrange a smooth meter replacement and continue enjoying the benefits they currently receive from RTS.”

More information on the RTS switch off can be found at www.ofgem.gov.uk/information-consumers/energy-advice-households/replacing-your-radio-teleswitch-electricity-meter.