Hundreds of thousands of households in the UK risk losing heating and hot water as outdated Radio Teleswitching Systems (RTS) will be permanently shut down on June 30, with energy companies struggling to replace them with smart meters in time. Currently, approximately 430,000 homes are still using RTS meters, and campaigners estimate over 300,000 may remain unupgraded by the deadline. Energy regulators and officials stress the urgency of accelerating replacements to prevent significant disruption, particularly for vulnerable customers.