Almost one million homes face having their cheap overnight electricity tariffs disrupted next month unless they replace their old meter with a smart meter.
Many homes could even lose access to heating and hot water if they do not agree to having their existing meters replaced.
This is because the technology powering older Radio Teleswitch (RTS) meters is set to be switched off from 31 March, with many owners of these devices facing an uncertain future.
Many of these meters are used for tariffs such as Economy 7 and 10, which offer cheaper overnight electricity rates.
These tariffs are popular with homes that want to save money by running appliances like washing machines and dishwashers overnight, or by using night-time storage heaters.
Update: A last minute extension of the deadline to replace Economy 7 meters has been revealed to This is Money after publication of this story, pushing back the switch-off of RTS to some point in 2025
To get these tariffs homes need to have one of three sorts of meter.
These households require a modern smart meter, a slightly older meter with a digital or mechanical clock or a meter that runs on 1980s technology called RTS.
Petering meters: Old RTS meters like this one may not work properly in a few weeks
The problem affects these older RTS meters, which piggyback off the long-wave channel for BBC Radio 4 in order to communicate with energy firms. Energy firms use RTS to switch a meter between peak and off-peak rates.
There are around 900,000 active RTS meters in the UK, according to figures from energy regulator Ofgem.
The contract between the BBC and energy firms to run the RTS system is ending on 31 March, although This is Money understands there are last-minute talks to try to extend this deadline, perhaps into 2025.
But if the RTS service is switched off then households face their meters not working properly, and possibly losing their hot water and heating. The timing of their meters may also not work properly.
Many energy firms are now contacting their RTS meter customers and urging them to switch to a smart meter.
An EDF email to one RTS meter customer reads: ‘Once this service is shut down, your meter could lose functionality and off-peak timings could change.
‘This could also result in the loss of important functions like heating and hot water.
‘You could also see increased costs, as when the RTS service ends your off-peak hours may no longer be picked up.
‘By upgrading your meter, you can continue to benefit from your off-peak hours without the need for the radio signal.’
The customer said: ‘EDF bombarded me a few months ago with emails telling me that my meter will no longer receive the signal (for Economy 7 switching) in 2024, which means my heating and hot water probably won’t work, so I will need a smart meter well beforehand due to demand.
‘So the previous harassment over the Government insisting that I have one has now turned into what could be classed as veiled threats.’
A similar email to an Octopus customer said: ‘The technology that switches your meter from peak to off-peak price is coming to an end in March 2024.
‘After the Radio Teleswitch Service (RTS) ends, your meter’s timings may not work as expected.
‘There’s a simple solution: we need to replace your meter. Book your smart meter install for a day that suits you, and we’ll handle the rest.’
But many households do not want a smart meter, or cannot have one installed due to connectivity issues.
Some readers have told This is Money that their smart meter bills are wrong, or that they feel bullied into getting one.
Homes that do not want to lose their RTS meter can in theory keep them, as it is not compulsory to have a smart meter fitted unless your old one is dangerous.
But keeping an RTS meter means a risk of losing access to the cheap overnight electricity of Economy 7 and 10 tariffs in just a few weeks, unless the deadline is extended.
Instead, households that keep RTS meters are likely to be switched to an alternative energy deal without off-peak rates.
An Ofgem spokesman said: ‘Ofgem expects suppliers to ensure appropriate metering arrangements are in place for their consumers.
‘This includes arranging for the replacement and upgrading of RTS metering equipment before any prospective end date and communicating clearly with consumers regarding this.’
Time-of-use tariffs such as Economy 7 and 10 energy deals are also compatible with mechanical meters that do not use radio to communicate with energy firms. Instead they rely on a clock-like timer to know when peak and offpeak times begin and end.
Households with these mechanical meters are unaffected by the current 31 March deadline for switching off the RTS service.
Many Economy 7 and 10 tariffs are also popular with electric vehicle (EV) owners, who want cheaper electricity when recharging their cars overnight.
However, many EV owners will be unaffected by the end of the RTS service, as most EV-specific energy deals already require homes to have a smart meter to sign up.
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